Haemophilia: From 4 Different Sources
A sex-linked hereditary bleeding disease associated with a deficiency of Factor VIII in the blood. Closely related to Christmas disease which has a deficiency of Factor IX. Transmitted by mothers with the recessive gene. Disease exclusive to males, blood failing to clot, resulting in bleeding from minor injury, such as tooth extraction. Possible blood in the urine (haematuria). No cure. A course of Goldenseal (liquid extract) 3-5 drops for 1 week, at bedtime, every 3 months, is said to be of value. Alternatives. Treatment. To increase tone in blood vessels (Gentian). To promote healing and toughen vessels (Horsetail). Blood in the urine (Shepherd’s Purse). Tendency of mucous surfaces to bleed (Goldenseal). Bleeding from the lungs (Elecampane); from the alimentary tract, bowel (American Cranesbill); from the throat (Sage). From the nose: inject equal parts Cider vinegar and water.
To strengthen vascular system. Tea. Equal parts: Horsetail, Nettles, Mullein. 1-2 teaspoons to each cup boiling water; infuse 15 minutes. One cup once or twice daily.
Topical. For bleeding of skin: Witch Hazel (distilled extract). Marigold tincture, cream, etc.
Diet. High calcium and phosphorus diet. Low salt. An article in a scientific journal describes how one sufferer arrested attacks with handful of unsalted peanuts.
Supplementation. Niacin, Vitamin C, Calcium, Zinc.
See: HAEMOSTATICS.
Treatment by a general medical practitioner or hospital specialist.
An inherited bleeding disorder caused by deficiency of a blood protein, factor VIII, which is essential for blood clotting. Haemophiliacs suffer recurrent bleeding, usually into their joints, which may occur spontaneously or after injury. The lack of factor is due to a defective gene, which shows a pattern of sex-linked inheritance; haemophilia affects males in most cases.
Episodes of bleeding are painful and, unless treated promptly, can lead to joint deformity. Injury, and even minor operations such as tooth extraction, may lead to profuse bleeding. Internal bleeding can lead to blood in the urine or extensive bruises.Haemophilia is diagnosed by bloodclotting tests, and by amniocentesis or chorionic villus sampling in a fetus.
Bleeding can be prevented or controlled by infusions of factor concentrates.
An inherited disorder of blood COAGULATION which results in prolonged bleeding even after minor injury. There is a de?ciency of factor VIII, an essential clotting factor in the coagulation cascade – the complex series of biochemical events that leads from injury of the wall of a blood vessel to the formation of a blood clot that checks bleeding. Haemophilia is a sex-linked recessive disorder (though a small number of cases arise by spontaneous mutation), so that, if females carry the disease, one-half of their sons will be affected and one-half of their daughters will be carriers. The sons of haemophiliacs are unaffected but one-half of their daughters will be carriers.
Haemophilia affects approximately 1:4,000 of the UK population but only 1:20,000 is severely affected. Severity of the disease depends upon the percentage, compared with normal, of factor VIII activity present. Less than 1 per cent and there will be spontaneous bleeding into joints and muscles; 1–5 per cent and there will be occasional spontaneous bleeding and severe bleeding after minor injury; 5–25 per cent and there will only be severe bleeding after major injury. Before treatment was available, severe haemophiliacs suffered from acute pain and deformity from bleeds into joints and muscles. Bleeding also occurred into the gut, kidneys and brain, and few survived past adolescence.
Freeze-dried factor VIII may be kept in domestic refrigerators. Haemophiliacs can use it to abort minor bleeds by reconstituting it and injecting it intravenously. More major bleeding or preparation for surgery involves raising factor VIII levels to 30–100 per cent by giving cryoprecipitate.
With treatment, most haemophiliacs lead normal lives, although obviously dangerous or contact sports should be avoided. Before donors of blood were screened for HEPATITIS B and C or for HIV infection (see AIDS/HIV), some individuals with haemophilia receiving factor VIII were unwittingly infected with those diseases. Today’s screening procedures make such infections very unlikely.
There is a National Haemophilia Register and each registered sufferer carries a card with details about his or her condition. Information may also be obtained from NHS haemophilia centres and the Haemophilia Society.
n. either of two hereditary disorders in which the blood clots very slowly, due to a deficiency of either of two *coagulation factors: haemophilia A, due to deficiency of Factor VIII (antihaemophilic factor); or haemophilia B, due to deficiency of Factor IX (Christmas factor). The patient may experience prolonged bleeding following any injury or wound, and in severe cases there is spontaneous bleeding into muscles and joints. Bleeding in haemophilia may be treated by recombinent-DNA-derived Factor VIII or plasma Factor VIII concentrate. Alternatively concentrated preparations of Factor VIII or Factor IX, obtained by freezing fresh plasma, may be administered (see cryoprecipitate). Haemophilia is controlled by a *sex-linked gene, which means that it is almost exclusively restricted to males: women can carry the gene – and pass it on to their sons – without being affected themselves. The genes encoding factors VIII and IX have been used in gene therapy trials for haemophilia. —haemophiliac n.
A hereditary disorder of blood coagulation which can only be distinguished from HAEMOPHILIA by laboratory tests. It is so-called after the surname of the ?rst case reported in this country. About one in every ten patients clinically diagnosed as haemophiliac has in fact Christmas disease. It is due to lack in the blood of Factor IX (see COAGULATION).... christmas disease
A coagulative blood protein that is a constituent of the COAGULATION cascade – an essential component in the clotting of blood. Those people with the inherited disorder, HAEMOPHILIA, have abnormally low amounts of factor VIII and so bleed more when cut. They are treated with a concentrated version to reduce the tendency to bleed.... factor viii
Haemarthrosis is the process of bleeding into, or the presence of blood in, a joint. It may occur as a result of major trauma (for example, fracture of the patella may lead to bleeding into the knee-joint), or, more commonly, following minor trauma. It may even occur spontaneously, in cases of HAEMOPHILIA or other disorders of blood clotting. If repeated several times, haemarthrosis may lead to FIBROSIS of the joint-lining and in?ammation of the cartilage, causing marked sti?ness and deformity.... haemarthrosis
Bruises, or contusions, result from injuries to the deeper layers of the skin or underlying tissues, with variable bleeding but without open wounds. Bruises range from a slight bluish discoloration, due to minimal trauma and haemorrhage, to a large black swelling in more severe cases. Diseases such as HAEMOPHILIA and SCURVY, which reduce COAGULATION, should be suspected when extensive bruises are produced by minor injuries. Bruises change colour from blue-black to brown to yellow, gradually fading as the blood pigment is broken down and absorbed. Bruising in the abdomen or in the back in the area of the kidneys should prompt the examining doctor to assess whether there has been any damage to internal tissues or organs. Bruising in children, especially repeated bruising, may be caused by physical abuse (see CHILD ABUSE and NON-ACCIDENTAL INJURY (NAI)). Adults, too, may be subjected to regular physical abuse.... bruises
When frozen plasma is allowed to thaw slowly at 4 °C, a proportion of the plasma protein remains undissolved in the cold thawed plasma and stays in this state until the plasma is warmed. It is this cold, insoluble precipitate that is known as cryoprecipitate. It can be recovered quite easily by centrifuging. Its value is that it is a rich source of factor VIII, which is used in the treatment of HAEMOPHILIA.... cryoprecipitate
These are caused when there are mutations or other abnormalities which disrupt the code of a gene or set of GENES. These are divided into autosomal (one of the 44 CHROMOSOMES which are not sex-linked), dominant, autosomal recessive, sex-linked and polygenic disorders.
Dominant genes A dominant characteristic is an e?ect which is produced whenever a gene or gene defect is present. If a disease is due to a dominant gene, those affected are heterozygous – that is, they only carry a fault in the gene on one of the pair of chromosomes concerned. A?ected people married to normal individuals transmit the gene directly to one-half of the children, although this is a random event just like tossing a coin. HUNTINGTON’S CHOREA is due to the inheritance of a dominant gene, as is neuro?bromatosis (see VON RECKLINGHAUSEN’S DISEASE) and familial adenomatous POLYPOSIS of the COLON. ACHONDROPLASIA is an example of a disorder in which there is a high frequency of a new dominant mutation, for the majority of affected people have normal parents and siblings. However, the chances of the children of a parent with the condition being affected are one in two, as with any other dominant characteristic. Other diseases inherited as dominant characteristics include spherocytosis, haemorrhagic telangiectasia and adult polycystic kidney disease.
Recessive genes If a disease is due to a recessive gene, those affected must have the faulty gene on both copies of the chromosome pair (i.e. be homozygous). The possession of a single recessive gene does not result in overt disease, and the bearer usually carries this potentially unfavourable gene without knowing it. If that person marries another carrier of the same recessive gene, there is a one-in-four chance that their children will receive the gene in a double dose, and so have the disease. If an individual sufferer from a recessive disease marries an apparently normal person who is a heterozygous carrier of the same gene, one-half of the children will be affected and the other half will be carriers of the disease. The commonest of such recessive conditions in Britain is CYSTIC FIBROSIS, which affects about one child in 2,000. Approximately 5 per cent of the population carry a faulty copy of the gene. Most of the inborn errors of metabolism, such as PHENYLKETONURIA, GALACTOSAEMIA and congenital adrenal hyperplasia (see ADRENOGENITAL SYNDROME), are due to recessive genes.
There are characteristics which may be incompletely recessive – that is, neither completely dominant nor completely recessive – and the heterozygotus person, who bears the gene in a single dose, may have a slight defect whilst the homozygotus, with a double dose of the gene, has a severe illness. The sickle-cell trait is a result of the sickle-cell gene in single dose, and sickle-cell ANAEMIA is the consequence of a double dose.
Sex-linked genes If a condition is sex-linked, affected males are homozygous for the mutated gene as they carry it on their single X chromosome. The X chromosome carries many genes, while the Y chromosome bears few genes, if any, other than those determining masculinity. The genes on the X chromosome of the male are thus not matched by corresponding genes on the Y chromosome, so that there is no chance of the Y chromosome neutralising any recessive trait on the X chromosome. A recessive gene can therefore produce disease, since it will not be suppressed by the normal gene of the homologous chromosome. The same recessive gene on the X chromosome of the female will be suppressed by the normal gene on the other X chromosome. Such sex-linked conditions include HAEMOPHILIA, CHRISTMAS DISEASE, DUCHENNE MUSCULAR
DYSTROPHY (see also MUSCLES, DISORDERS OF – Myopathy) and nephrogenic DIABETES INSIPIDUS.
If the mother of an affected child has another male relative affected, she is a heterozygote carrier; half her sons will have the disease and half her daughters will be carriers. The sister of a haemophiliac thus has a 50 per cent chance of being a carrier. An affected male cannot transmit the gene to his son because the X chromosome of the son must come from the mother; all his daughters, however, will be carriers as the X chromosome for the father must be transmitted to all his daughters. Hence sex-linked recessive characteristics cannot be passed from father to son. Sporadic cases may be the result of a new mutation, in which case the mother is not the carrier and is not likely to have further affected children. It is probable that one-third of haemophiliacs arise as a result of fresh mutations, and these patients will be the ?rst in the families to be affected. Sometimes the carrier of a sex-linked recessive gene can be identi?ed. The sex-linked variety of retinitis pigmentosa (see EYE, DISORDERS OF) can often be detected by ophthalmoscopic examination.
A few rare disorders are due to dominant genes carried on the X chromosome. An example of such a condition is familial hypophosphataemia with vitamin-D-resistant RICKETS.
Polygenic inheritance In many inherited conditions, the disease is due to the combined action of several genes; the genetic element is then called multi-factorial or polygenic. In this situation there would be an increased incidence of the disease in the families concerned, but it will not follow the Mendelian (see MENDELISM; GENETIC CODE) ratio. The greater the number of independent genes involved in determining a certain disease, the more complicated will be the pattern of inheritance. Furthermore, many inherited disorders are the result of a combination of genetic and environmental in?uences. DIABETES MELLITUS is the most familiar of such multi-factorial inheritance. The predisposition to develop diabetes is an inherited characteristic, although the gene is not always able to express itself: this is called incomplete penetrance. Whether or not the individual with a genetic predisposition towards the disease actually develops diabetes will also depend on environmental factors. Diabetes is more common in the relatives of diabetic patients, and even more so amongst identical twins. Non-genetic factors which are important in precipitating overt disease are obesity, excessive intake of carbohydrate foods, and pregnancy.
SCHIZOPHRENIA is another example of the combined effects of genetic and environmental in?uences in precipitating disease. The risk of schizophrenia in a child, one of whose parents has the disease, is one in ten, but this ?gure is modi?ed by the early environment of the child.... genetic disorders
One of two SEX CHROMOSOMES. Every normal female body cell has a pair of X chromosomes. Men have only one X chromosome and this is paired with a Y chromosome. The sex cells in men and women each have one X and one Y chromosome. Certain diseases are linked to the presence of an X chromosome: these include HAEMOPHILIA (see GENETIC DISORDERS). (See also GENES.)... x chromosome
An archaic term meaning constitutional or inherited state giving an individual a predisposition towards a disease, a group of diseases or a structural or metabolic abnormality. An example is HAEMOPHILIA, a bleeding disorder.... diathesis
Inspection of a FETUS by passing a ?breoptic instrument called a fetoscope through the abdominal wall of a pregnant woman into her UTERUS. The procedure is usually conducted in the 18th to 20th week of pregnancy to assess the fetus for abnormalities and to take blood samples to preclude diseases such as HAEMOPHILIA, DUCHENNE MUSCULAR DYSTROPHY and sickle-cell ANAEMIA. The procedure should be used only if there is a serious possibility of abnormality, the presence of which will usually have been indicated by other screening tests such as ULTRASOUND and tests of blood obtained by (intrauterine) cordocentesis (withdrawal of blood by syringe inserted into the umbilical cord).... fetoscopy
The escape of blood from any of the blood vessels, normally in response to some trauma, or as a result of a clotting disorder such as HAEMOPHILIA. The bleeding may be external – for example, following a skin laceration; or it may be internal – for example, haematemesis (bleeding into the stomach), haemoptysis (bleeding from the lungs), or haematuria (bleeding from the kidneys or urinary tract). For more information about these conditions, see separate entries.
Bleeding into or around the brain is a major concern following serious head injuries, or in newborn infants following a di?cult labour. Haemorrhage is classi?ed as arterial – the most serious type, in which the blood is bright red and appears in spurts (in severe cases the patient may bleed to death within a few minutes); venous – less serious (unless from torn varicose veins) and easily checked, in which the blood is dark and wells up gradually into the wound; and capillary, in which the blood slowly oozes out of the surface of the wound and soon stops spontaneously. Haemorrhage is also classi?ed as primary, reactionary, and secondary (see WOUNDS). Severe haemorrhage causes SHOCK and ANAEMIA, and blood TRANSFUSION is often required.
When a small artery is cut across, the bleeding stops in consequence of changes in the wall of the artery on the one hand, and in the constitution of the blood on the other. Every artery is surrounded by a ?brous sheath, and when cut, the vessel retracts some little distance within this sheath and a blood clot forms, blocking the open end (see COAGULATION). When a major blood vessel is torn, such spontaneous closure may be impossible and surgery is required to stop the bleeding.
Three main principles are applicable in the control of a severe external haemorrhage: (a) direct pressure on the bleeding point or points;
(b) elevation of the wounded part; (c) pressure on the main artery of supply to the part.
Control of internal haemorrhage is more dif?cult than that of external bleeding. First-aid measures should be taken while professional help is sought. The patient should be laid down with legs raised, and he or she should be reassured and kept warm. The mouth may be kept moist but no ?uids should be given. (See APPENDIX 1: BASIC FIRST AID.)... haemorrhage
A drug used in the control of bleeding. It inhibits the activation of PLASMINOGEN and FIBRINOLYSIS, and may be useful when bleeding cannot be stopped – for instance, dental extraction in HAEMOPHILIA. The drug is also useful in MENORRHAGIA.... tranexamic acid
A genetically determined blood disorder in which the affected person suffers episodes of spontaneous bleeding similar to that occurring in people with HAEMOPHILIA. It may be associated with a lack of FACTOR VIII (see COAGULATION) in the blood. The disorder is inherited as an autosomal dominant gene (see GENETIC DISORDERS).... von willebrand’s disease
A group of drugs used to treat bleeding disorders and to control bleeding. Haemostatic preparations that help blood clotting are given to people who have deficiencies of natural clotting factors. For example, factor VIII is used to treat haemophilia. Drugs that prevent the breakdown of fibrin in clots, such as tranexamic acid, can also improve haemostasis.... haemostatic drugs
Sex-linked genetic disorders in which the abnormal gene or genes (the causative factors) are located on the X chromosome. Almost all affected people are males. Haemophilia, fragile X syndrome. and colour vision deficiency are examples.... x-linked disorders
(clotting factors) a group of substances present in blood plasma that, under certain circumstances, undergo a series of chemical reactions leading to the conversion of blood from a liquid to a solid state (see blood coagulation). Although they have specific names, most coagulation factors are referred to by an agreed set of Roman numerals (e.g. *Factor VIII, *Factor IX). Lack of any of these factors in the blood results in the inability of the blood to clot. See also haemophilia.... coagulation factors
n. a synthetic derivative of *vasopressin that causes a decrease in urine output and is used to treat diabetes insipidus and nocturnal *enuresis. It is also effective in mild haemophilia and von Willebrand’s disease. Side-effects include stomach cramps, headache, and flushing of the skin.... desmopressin
Acquired immune deficiency syndrome, a deficiency of the immune system due to infection with HIV (human immunodeficiency virus). In most countries, illness and death from is a growing health problem, and there is, as yet, no cure or vaccine.
does not develop in all people infected with. The interval between infection and the development of is highly variable. Without treatment, around half of those people infected will develop within 8–9 years.
is transmitted in body fluids, including semen, blood, vaginal secretions, and breast milk. The major methods of transmission are sexual contact (vaginal, anal, or oral), blood to blood (via transfusions or needle-sharing in drug users), and mother to fetus. has also been transmitted through blood products given to treat haemophilia, artificial insemination by donated semen, and kidney transplants; but improved screening has greatly reduced these risks. is not spread by everyday contact, such as hugging or sharing crockery. The virus enters the bloodstream and infects cells that have a particular receptor, known as the CD4 receptor, on their surface. These cells include a type of white blood cell (a CD4 lymphocyte) responsible for fighting infection and cells in other tissues such as the brain. The virus reproduces within the infected cells, which then die, releasing more virus particles into the blood. If the infection is left untreated, the number of CD4 lymphocytes falls, resulting in greater susceptibility to certain infections and some types of cancer.
Some people experience a short-lived illness similar to infectious mononucleosis when they are first infected with. Many individuals have no obvious symptoms; some have only vague complaints, such as weight loss, fevers, sweats, or unexplained diarrhoea, described as -related complex.
Minor features of infection include skin disorders such as seborrhoeic dermatitis. More severe features include persistent herpes simplex infections, oral candidiasis (thrush), shingles, tuberculosis, and shigellosis. may also affect the brain, causing a variety of neurological disorders, including dementia.
Certain conditions, known as AIDSdefining illnesses, are characteristic of full-blown. These include cancers (Kaposi’s sarcoma and lymphoma of the brain), and various infections (pneumocystis pneumonia, cytomegalovirus infection, toxoplasmosis, diarrhoea due to CRYPTOSPORIDIUM or ISOSPORA, candidiasis, disseminated strongyloidiasis, and cryptococcosis), many of which are described as opportunistic infections.
Confirmation of infection involves testing a blood sample for the presence of antibodies to. Diagnosis of fullblown is based on a positive test along with the presence of an AIDSdefining illness.
The risk of infection with can be reduced by practising safer sex. Intravenous drug users should not share needles. There is a small risk to health workers handling infected blood products or needles, but this risk can be minimized by safe practices.
Treatment of infection with a combination of antiviral drugs can slow the disease’s progress, and may prevent the development of full-blown. The 2 main types of antiviral drug used are protease inhibitors, such as indinavir, and reverse transcriptase inhibitors such as zidovudine. Treatment is also available for -defining illnesses.... aids
(Christmas factor) a *coagulation factor normally present in blood. Deficiency of the factor results in *haemophilia B.... factor ix
adj. describing genes (or the characteristics controlled by them) that are carried on the sex chromosomes, usually the *X chromosome. The genes for certain disorders, such as *haemophilia, are carried on the X chromosome; these genes and disorders are described as X-linked. Since most of these sex-linked genes are *recessive, men are more likely to have the diseases since they have only one X chromosome; women can carry the genes but their harmful effects are usually masked by the dominant (normal) alleles on their second X chromosome.... sex-linked
Disorders resulting from abnormalities in any of the components of blood or from infection. Disorders include types of anaemia, polycythaemia, bleeding disorders, and unwanted clot formation (thrombosis), hypoalbuminaemia (albumin deficiency) and agammaglobulinaemia (deficiency of gamma-globulin). Blood disorders such as sickle cell anaemia, thalassaemia, and haemophilia are inherited. Bone marrow cancers that affect production of blood components include leukaemia, polycythaemia vera, and multiple myeloma. Blood poisoning is usually due to septicaemia or a toxin such as carbon monoxide. Some drugs can cause blood abnormalities as a side effect. (See also anaemia, haemolytic; anaemia, iron-deficiency; anaemia, megaloblastic; malaria; hyperbilirubinaemia.)... blood, disorders of
A branch of genetics concerned with the alteration of the genetic material of an organism to produce a desired change in the organism’s characteristics. In practice, genetic engineering has mainly been used to mass-produce a variety of substances that are useful in medicine. A gene responsible for making a useful protein is identified and inserted into another cell (most often a bacterium or a yeast) that reproduces rapidly to form a colony of cells containing the gene. This colony produces the protein in large amounts. Some human hormones (notably insulin and growth hormone) and proteins such as factor VIII (used to treat haemophilia) are made in this way.... genetic engineering
The transmission of characteristics and disorders from parents to their children through the influence of genes. Genes are the units of DNA (deoxyribonucleic acid) that are contained in a person’s cells; controls all growth and functioning of the body. Half of a person’s genes come from the mother, half from the father.
Genes are organized into chromosomes in the cell nucleus. Genes controlling most characteristics come in pairs, 1 from the father, the other from the mother. Everyone has 22 pairs of chromosomes (called autosomes) bearing these paired genes, in addition to 2 sex chromosomes. Females have 2 X chromosomes; males have an X and a Y chromosome.
Most physical characteristics, many disorders, and some mental abilitiesand aspects of personality are inherited. The inheritance of normal traits and disorders can be divided into those controlled by a single pair of genes on the autosomal chromosomes (unifactorial inheritance, such as eye colour); those controlled by genes on the sex chromosomes (sex-linked inheritance, such as haemophilia); and those controlled by the combination of many genes (multifactorial inheritance, such as height).
Either of the pair of genes controlling a trait may take any of several forms, known as alleles. For example, the genes controlling eye colour exist as 2 main alleles, coding for blue and brown eye colour. The brown allele is dominant over blue in that it “masks” the blue allele, which is called recessive to the brown allele. Only 1 of the pair of genes controlling a trait is passed to a child from each parent. For example, someone with the brown/blue combination for eye colour has a 50 per cent chance of passing on the blue gene, and a 50 per cent chance of passing on the brown gene, to any child. This factor is combined with the gene coming from the other parent, according to dominant or recessive relationships, to determine the child’s eye colour. Certain genetic disorders are also inherited in a unifactorial manner (for example, cystic fibrosis and achondroplasia).
Sex-linked inheritance depends on the 2 sex chromosomes, X and Y. The most obvious example is gender. Male gender is determined by genes on the Y chromosome, which is present only in males. Any faults in a male’s genes on the X chromosome tend to be expressed outwardly because such a fault cannot be masked by the presence of a normal gene on a 2nd X chromosome (as it can in females). Faults in the genes of the X chromosome include those responsible for colour vision deficiency, haemophilia, and other sex-linked inherited disorders, which almost exclusively affect males.
Multifactorial inheritance, along with the effects of environment, may play a part in causing certain disorders, such as diabetes mellitus and neural tube defects.... inheritance
A change in a cell’s DNA. Many mutations are harmless; however, some are harmful, giving rise to cancers, birth defects, and hereditary diseases. Very rarely, a mutation may be beneficial.
A mutation results from a fault in the replication of when a cell divides. A daughter cell inherits some faulty , and the fault is copied each time the new cell divides, creating a cell population containing the altered.
Some mutations occur by chance. Any agent that makes mutations more likely is called a mutagen.
There are several types of mutation. Point mutations affect only one gene and may lead to the production of defective enzymes or other proteins. In other mutations, chromosomes (or parts of them) are deleted, added, or rearranged. This type may produce greater disruptive effects than point mutations.
If a mutated cell is a somatic (body) cell, it can, at worst, multiply to form a group of abnormal cells. These cells often die out, are destroyed by the body’s immune system, or have only a minor effect. Sometimes, however, they may become a tumour.
A mutation in a germ cell (immature egg or sperm) may be passed on to a child, who then has the mutation in all of his or her cells.
This may cause an obvious birth defect or an abnormality in body chemistry.
The mutation may also be passed on to the child’s descendants.
Genetic disorders (such as haemophilia and achondroplasia) stem from point mutations that occurred in the germ cell of a parent, grandparent, or more distant ancestor.
Chromosomal abnormalities (such as Down’s syndrome) are generally due to mutations in the formation of parental eggs or sperm.... mutation
n. inflammation of one or more joints, characterized by pain, swelling, warmth, redness of the overlying skin, and diminished range of joint motion. There are four basic subgroups of arthritis: noninflammatory arthritis, including *osteoarthritis, *neuropathic arthritis, and *osteochondritis dissecans; inflammatory arthritis, including *rheumatoid arthritis, *gout, *psoriatic arthritis, and *juvenile idiopathic arthritis; infectious arthritis, including *septic arthritis; and haemorrhagic arthritis, including haemophilic arthritis (which occurs in patients with haemophilia). Arthritis may be monoarticular (involving one joint), pauciarticular (involving four or fewer joints), or polyarticular (involving five or more joints, either simultaneously or in sequence). Diagnosis is based on clinical and laboratory findings, including X-rays, blood tests, and where necessary analysis of synovial fluid obtained by *arthrocentesis. Treatment is specific for each subgroup and may include any combination of supportive measures with activity modification, analgesics, anti-inflammatory medications (e.g. *NSAIDs), *disease-modifying antirheumatic drugs (DMARDs), corticosteroids, and surgical procedures, such as joint replacement (see arthroplasty). —arthritic adj.... arthritis
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