21. Homocystinuria homocystinuria is an inherited disorder of the of the amino acid methionine. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

22. Homocystinuria Management In homocystinuria, however, inactivity of CBS prevents homocysteine from The clinical consequences of homocystinuria are multiple and severe, http://www.meadjohnson.com/metabolics/homocystinuria.html

Homocystinuria: Background Harvey Levy, M.D. Metabolic Clinic (Genetic Service), Children’s Hospital, Boston, MA Although there are several metabolic disorders in which homocystine is secreted in the urine, the major of these disorders, referred to as homocystinuria (or HCU), is due to cystathionine ß-synthase (CBS) deficiency. CBS is an enzyme involved at the branching point between transsufuration and remethylation in methionine degradation. Normally at this point, most homocysteine is converted to cystathionine and much less is remethylated back to methionine. In homocystinuria, however, inactivity of CBS prevents homocysteine from transsulfuration to cystathionine and diverts it via remethylation to methionine. Consequently, the following biochemical abnormalities occur: Increased methionine Increased homocysteine Increased homocystine (homocysteine—homocysteine) Increased mixed disulfide (homocysteine—cysteine) Decreased cystine (cysteine—cysteine) Although increased methionine is often the first indicator of homocystinuria, the toxic metabolite is homocysteine. It is not entirely known how accumulated homocysteine produces damage; the predominant concept is that it binds to cysteine residues of tissue proteins and prevents the formation of cysteine-cysteine disulfide bonding within the protein, which is critical for proper protein folding and conformation. The clinical consequences of homocystinuria are multiple and severe, including dislocation of the ocular lenses (ectopia lentis), mental retardation, skeletal abnormalities, and thromoboembolic events (1).

23. Dr. Koop - Homocystinuria homocystinuria is an inherited disorder of the of the amino acid methionine. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

24. Dr. Koop - Homocystinuria homocystinuria is an inherited disorder of the of the amino acid methionine. http://www.drkoop.com/ency/93/001199.html

Home Health Reference Homocystinuria Jul 29, 2005 Search: Dr.Koop MEDLINE Diseases Symptoms Procedures Natural Medicine ... Drug Library Inside DrKoop News Archive Animations Health Videos Health Tools ... Newsletters Homocystinuria Injury Disease Nutrition Poison ... Prevention Homocystinuria Definition: Homocystinuria is an inherited disorder of the metabolism of the amino acid methionine. Alternative Names: Cystathionine beta synthase deficiency Causes, incidence, and risk factors: Homocystinuria is inherited as an autosomal recessive trait, which means that the child must inherit the defective gene from both parents to be seriously affected. Typical problems seen in people with homocystinuria are nearsightedness dislocation of the lens of the eye, and a tendency to develop blood clots in the veins and arteries. Newborn infants appear normal, and early symptoms, if present at all, are vague and may occur as mildly delayed development or failure to thrive . Increasing visual problems may lead to diagnosis of this condition when the child, on examination, is discovered to have dislocated lenses and nearsightedness. Some degree of mental retardation is usually seen, but some affected people have normal IQs. When mental retardation is present, it is generally progressive if left untreated. The condition can also increase the risk for psychiatric disorders.

25. Dr. Koop - Homocystinuria homocystinuria is an inherited disorder of the of the amino acid methionine. http://www.drkoop.com/ency/93/001199trt.html

Home Health Reference Homocystinuria Jul 29, 2005 Search: Dr.Koop MEDLINE Diseases Symptoms Procedures Natural Medicine ... Drug Library Inside DrKoop News Archive Animations Health Videos Health Tools ... Newsletters Homocystinuria Injury Disease Nutrition Poison ... Prevention Homocystinuria Alternative Names: Cystathionine beta synthase deficiency Treatment: There is no specific cure for homocystinuria. However, many people respond to high doses of vitamin B-6 (also known as pyridoxine). Slightly less than half of patients respond to this treatment; those that do respond need supplemental vitamin B-6 for the rest of their lives. Those who do not respond require a low methionine diet, and most will need treatment with trimethylglycine (a medication also known as betaine). Neither a low-methionine diet nor medication will improve existing mental retardation. Medication and diet should be closely supervised by a physician with experience treating homocystinuria. A normal dose folic acid supplement and occasionally added cysteine (an amino acid) in the diet is helpful. Expectations (prognosis): Although no specific cure exists for homocystinuria, approximately half of the affected people can be helped by vitamin B-6 therapy.

26. What Is Homocystinuria? Health care centre, teaching and research hospital Vancouver Hospital and Health Sciences Centre in British Columbia Canada. http://www.vanhosp.bc.ca/html/wellness_amdc_findout_homocystinuria_whatis.html

Home Adult Metabolic Diseases Find Out About a Specific Disease Homocystinuria What is Homocystinuria? How do People Get Homocystinuria? How is Homocystinuria Treated? How can Friends and Family Help? Resources ... References What is Homocystinuria? Homocystinuria (HOMO-SISTIN-UREA) is a genetic disorder that affects how protein is broken down in the body. It is therefore called a nutritional or metabolic disorder. About one out of 200,000 babies are born with homocystinuria each year in Canada. Homocystinuria can be treated with drugs, with diet or with a combination of both. One of the drugs used is pyridoxine or vitamin B6 . About half the people affected by homocystinuria are very responsive to vitamin B6 and do not need any other special treatment. These people are said to be " pyridoxine responsive ." There are 2 other groups of people with homocystinuria: those who partly respond to pyridoxine, and those who have no response to pyridoxine. Both these groups of people will need to take other medications and follow a special diet. Amino acids are the building blocks of protein. Of the 20 amino acids found in body protein, 8 cannot be made by adults and must be obtained from foods. These are considered

27. How Do People Get Homocystinuria? Health care centre, teaching and research hospital Vancouver Hospital and Health Sciences Centre in British Columbia Canada. http://www.vanhosp.bc.ca/html/wellness_amdc_findout_homocystinuria_how.html

Home Adult Metabolic Diseases Find Out About a Specific Disease Homocystinuria ... What is Homocystinuria? How do People Get Homocystinuria? How is Homocystinuria Treated? How can Friends and Family Help? Resources References How do People Get Homocystinuria? Homocystinuria is an inborn error of metabolism. It is genetic. This means that the person has the disorder from the time they are conceived. At conception, the baby receives two sets of genetic material, one from the mother, and one from the father. This genetic material, called DNA , acts as a recipe for the baby's development. DNA includes information about the baby's eye and hair colour, sex and even whether the baby will be right or left-handed. DNA comes in units called genes . Each pair of genes gives directions to a certain part of the body. In homocystinuria, there is a problem with the genes that give information on how the body breaks down protein. The disorder is caused by getting two copies of the faulty gene that gives the wrong instructions. One copy comes from the mother and one comes from the father. If the child inherits only one copy of the gene, they are a carrier for homocystinuria but are not affected. There is a 1 in 4, or 25% chance that two carriers of the gene will have a baby with homocystinuria. Boys and girls are equally affected. Children born to carriers have: a 25% chance of having homocystinuria

28. Homocystinuria - Genetics Home Reference Where can I find additional information about homocystinuria? What if I still have specific questions about homocystinuria? What glossary definitions help http://ghr.nlm.nih.gov/condition=homocystinuria

Home What's New Browse Handbook ... Search Homocystinuria Related Gene(s) Quick links to this topic MedlinePlus Health Information Educational resources Information pages Patient support For patients and families Gene Reviews Clinical summary Gene Tests DNA test labs ClinicalTrials.gov Research studies PubMed Recent literature OMIM Genetic disorder catalog References Homocystinuria On this page: What is homocystinuria? How common is homocystinuria? ... help with understanding homocystinuria? What is homocystinuria? Homocystinuria is an inherited disorder in which the body is unable to process certain amino acids (the building blocks of proteins) properly. The most common form of the condition is caused by the lack of an enzyme called cystathionine beta-synthase. This form of homocystinuria is characterized by dislocation of the lens in the eye, an increased risk of abnormal blood clots, and skeletal abnormalities. Problems with development and learning are also evident in some cases. Less common forms of homocystinuria are caused by a lack of other enzymes involved in processing amino acids. These disorders can cause mental retardation, seizures, problems with movement, and a blood disorder called megaloblastic anemia. How common is homocystinuria?

29. HOMOCYSTINURIA SUPPORT The introduction gives basic details on what homocystinuria is about. Some basic information about what kinds of food homocystinuria patients can eat is http://www.hcusupport.com/

INTRODUCTION WHAT IS HCU DIET SIDE EFFECTS ... REFERENCES W ELCOME TO MY HOMOCYSTINURIA WEB PAGE !!! Update June 2004 : In 1999, this site was developed in order to help people with HOMOCYSTINURIA. In the last few years I was not able to update this site because of having series of health problems. Since I feel much better right now I will be updating it on a on a regular basis. Recently I have also completed a few computer courses on web development. So I am confident of improving this site to be more useful. My name is Bharat Ramanujam, I live in California. I am 22 yrs old. I was diagnosed at the age of 2 that I had a condition called Homocystinuria, which is due to the absence of an enzyme in my body. This enzyme is called Cystathionine ß Synthase. Since I missed some of my classes in high school due to health problems, I completed some courses in a community college for the past three years. Some of the courses I have completed are computer, math, weight training, English, Yoga , geology, and many more. My hobbies are reading about animals, listening to music, surfing the internet , watching action movies and watching basketball games. I am also a volunteer at Los Angeles Zoo. I also have a website called www.endangeredandrareanimals.com

30. INTRODUCTION homocystinuria is an inborn error of methonine metabolism and was discovered homocystinuria (HCU), is a particular type of metabolic disorder similar to http://www.hcusupport.com/Introduction.htm

Homocystinuria is an inborn error of methonine metabolism and was discovered in 1962 independently in Northern Ireland by Carson and Neill and in the United States by Gerritsen et al. The basic defect was defined by Mudd and his co-workers in 1964 as a deficiency of the hepatic enzyme Cystathionine ß Synthase. ( Nina A.J. Carson, The Treatment of Inherited Metabolic Disorders Homocystinuria (HCU), is a particular type of metabolic disorder similar to Phenylketonuria (PKU), Methylmalonic Acidemia(MMA) and Tyrosinemia. Each of these disorders require food products which are low in particular types of amino-acids. i.e. Methonine in the case of HCU, Phenylalanine in the case of PKU. . A simple explanation of the disorders such as HCU is given below. Methonine, an amino acid, which is present in regular food protein undergoes the following steps in digestion in the body Methonine Homocyst(e)ine Cystathionine synthase (absent in Homocystinuria) Cyst(e)ine The conversion of Methonine to Homocyst(e)ine takes place without any problem but Homocyst(e)ine to Cyst(e)ine does not happen because of absence of the enzyme, Cystathionine

31. Disorders homocystinuria is a metabolic disorder caused by a defective enzyme homocystinuria only emerges when two carriers of the defective gene have children http://www.pku-allieddisorders.org/allieddisorders.htm

Homocystinuria MSUD Organic Acidemias Phenylketonuria Tyrosinemia Urea Cycle Disorders All of the disorders listed above have a common thread. Each disorder is a metabolic disorder requiring a low protein diet along with strict medical supervision. Together we can make a difference as we reach out and across to one another For Links and support group information, Please click here For low protein recipes see this site: www.lowprotein.com Mansfield, MA 02048 Home Research Resources Disorders ... Disorders Homocystinuria Homocystinuria is a metabolic disorder caused by a defective enzyme (cystathionine synthetase) needed to digest the amino acid in protein called methionine. Once diagnosed, the initial treatment would be changing the baby formula to a special medical formula, which does not contain methionine. Along with the medical formula the child will maintain a low protein/low methionine diet for life. Some of the more dominant systems of HCU include mental retardation, ectopia lentis (dislocation of the lenses of the eye), osteoporosis, delays in reaching developmental milestones, the formation of blood clots that may lead to life-threatening complications.

32. ► Homocystinuria A medical encycopedia article on the topic homocystinuria. http://www.umm.edu/ency/article/001199.htm

var MenuLinkedBy='AllWebMenus [2]', awmBN='530'; awmAltUrl=''; Disease Nutrition Surgery Symptoms Injury ... Encyclopedia (English) Toggle English Spanish Homocystinuria Overview Symptoms Treatment Prevention Definition: Homocystinuria is an inherited disorder involving the metabolism of the amino acid methionine. Causes, incidence, and risk factors: Homocystinuria is inherited as an autosomal recessive trait. Usual findings in homocystinuria are myopia nearsightedness dislocation of the lens of the eye, and a tendency to develop venous and arterial clots ( thrombi Newborn infants appear normal, and early symptoms, if present at all, are vague and may occur as mildly delayed development or failure to thrive . Increasing visual problems may lead to diagnosis of this condition when the child, on examination, is discovered to have dislocated lenses and myopia. Some degree of mental retardation is usually seen, but some affected people have normal IQs. When mental retardation is present, it is generally progressive if left untreated. Psychiatric disease can also result. Homocystinuria has several features in common with Marfan syndrome including dislocation of the lens, a tall, thin build with long limbs; spidery fingers (

33. ► Homocystinuria A medical encycopedia article on the topic homocystinuria. http://www.umm.edu/ency/article/001199sym.htm

var MenuLinkedBy='AllWebMenus [2]', awmBN='530'; awmAltUrl=''; Disease Nutrition Surgery Symptoms Injury ... Encyclopedia (English) Toggle English Spanish Homocystinuria Overview Symptoms Treatment Prevention Symptoms: A family history of homocystinuria Nearsightedness Flush across the cheeks Tall, thin build Long limbs High-arched feet ( pes cavus Knock-knees ( genu valgum Pectus excavatum Pectus carinatum Mental retardation Psychiatric disease Signs and tests: During physical examination of the child, the health care provider may notice a tall, thin (Marfanoid) stature with pectus deformity of the chest or scoliosis. If there is poor or double vision, an ophthalmologist should perform a dilated eye exam where dislocation of the lens of the eye or myopia may be observed. There may be a history of frequent thromboembolic episodes. Mental retardation, slightly low IQ or psychiatric disease are common. Tests: A skeletal X-ray shows osteoporosis. A standard ophthalmic exam confirms myopia and dislocated lens. Affected children may also have cataracts glaucoma , and retinal detachment An amino acid screen of blood and urine shows elevated methionine and homocysteine levels.

34. Vitaflo International - HCU Homocystinuria UK based company specialising in PKU diet and inherited metabolic disorder foods, designed for persons with genetic metabolic disorders including http://www.vitaflo.co.uk/homocystinuria.php

var MenuLinkedBy='AllWebMenus [4]', awmBN='616'; awmAltUrl=''; Homocystinuria HCU gel HCU express Cystine AA Supplement Related Products: Vitabite FlavourPac Treatment strategies aimed at lowering total homocysteine may be pharmacological or dietary or a combination of both. (1) Pharmacological doses of pyridoxine (B6) lead to an increase of residual CBS activity in B6 responsive HCU. Response to B6 is variable and is influenced by folate depletion. Folate is therefore given in conjunction with B6. Betaine will lower the plasma homocysteine whilst raising the less toxic methionine through the process of remethylation. (2) Dietary treatment aims to reduce the plasma concentration of total homocysteine by means of a methionine restricted, cystine enriched, diet in those who are non-pyridoxine or partially pyridoxine responsive. Essential components of diet: Methionine from normal dietary sources - since methionine is an essential amino acid it cannot be excluded but must be restricted to individual tolerance and measured using an exchange system of either 1g protein exchanges or 20mg methionine exchanges

35. Manbir Online ... Homocystinuria In homocystinuria there is impaired conversion of homocysteine to methionine homocystinuria is relatively common in Ireland (1 in 60000 births) but rare http://www.manbir-online.com/htm2/homocyctin.htm

Home Medi News Medical Tidbits Interesting Topics ... Ask a Question Homocystinuria Home Medi News Medical Tidbits Interesting Topics ... Ask a Question It is an inborn error of Methionine metabolism in which there is deficiency of enzyme cystathionine b -synthase Homocysteine is converted to methionine. In homocystinuria there is impaired conversion of homocysteine to methionine, The sulfur atom of the essential amino acid methionine is transferred ultimately to cysteine by the transsulfuration pathway. In one of these steps, homocysteine condenses with serine to form cystathionine. This reaction is catalyzed by the pyridoxal phosphate-dependent enzyme cystathionine b -synthase. Homocysteine and methionine accumulate in cells and body fluids; cysteine synthesis is impaired, resulting in reduced concentrations of this amino acid and its disulfide form cystine. Homocystinuria is relatively common in Ireland (1 in 60,000 births) but rare elsewhere (less than 1 in 200,000 births). This genetic defect is also seen in consanguineous marriages.

36. Homocystinuria Definition - Medical Dictionary Definitions Of Popular Medical Te Online Medical Dictionary and glossary with medical definitions. http://www.medterms.com/script/main/art.asp?articlekey=3776

37. Homocystinuria Facts A fact sheet that briefly describes homocystinuria in infants and young children, its symptoms, treatments, and general outcomes. http://www.doh.wa.gov/EHSPHL/PHL/Newborn/homocystinuria.htm

You are here: DOH Home EHSPHL Home PHL Home NBS Home ... Employees Homocystinuria Primary Defect Deficiency or absence of an enzyme necessary for the breakdown of the amino acid methionine results in build up of methionine in the blood and elevated excretion of homocystine in the urine. Screening Test Historically screening has been based on measurement of methionine in the dried blood spot using a bacterial inhibition assay similar to the original Guthrie assay for PKU. Screening is now possible using tandem mass spectrometry (MS/MS). Predictive value should be high. Because of delayed accumulation of methionine if residual enzyme activity is present, screening may be more effective at 2 to 4 weeks of age for these infants. Genetic, autosomal recessive. A number of specific genetic defects have been identified. With some, residual enzyme activity may occur, resulting in moderation of symptoms and delay in accumulation of elevated levels of methionine. About one in every 200,000 babies in the United States is born with homocystinuria. If Untreated There is wide variation in clinical course for affected infants. Clinical features include: circulatory blood clotting (thromboembolism), physical and mental developmental disabilities. Approximately half die by age 25 due to thromboembolism. Developmental delay and physical defects affect most. The most common defect (cystathionine b-synthase deficiency) can be classified as either responsive or non-responsive to treatment with vitamin B6. This may be related to residual enzyme activity needed for response. Those who are not responsive have more severe clinical course.

38. Homocystinuria General Overview Frequently asked questions about homocystinuria that briefly describes the body’s normal metabolic process, the effects and most common treatments. http://www.doh.wa.gov/EHSPHL/PHL/Newborn/homocysgo.htm

You are here: DOH Home EHSPHL Home PHL Home NBS Home »Homocystinuria General Overview Page Search Employees Site Directory: Homocystinuria General Overview Page Disorders Health Professional's Page Parents Page Related Links ... Contact NBS What should I know about Homocystinuria? (click here for printer friendly version of this information in pdf format) Please see the viewer page for free software to enable viewing of pdf files. What is Homocystinuria? Is there only one form of homocystinuria? How does the body normally process methionine? What happens to methionine in a child with homocystinuria? ... How common is homocystinuria? Q. What is Homocystinuria? A. Homocystinuria is a treatable disorder that affects the way the body processes protein. Children with homocystinuria cannot use a part of the protein called methionine. If left untreated, methionine and related molecules build up in the bloodstream and lead to brain damage and other disabilities. Q. Is there only one form of homocystinuria? A. No, there are several forms of homocystinuria.

39. GeneReviews: Homocystinuria Caused By Cystathionine Beta-Synthase Deficiency Your browser does not support HTML frames so you must view homocystinuria Caused by Cystathionine BetaSynthase Deficiency in a slightly less readable form. http://www.genetests.org/query?dz=homocystinuria

40. Homocystinuria homocystinuria is a rare metabolic condition characterized by an excess of the compound homocystine in the urine. The condition may result from deficiency http://www.bchealthguide.org/kbase/nord/nord463.htm

var hwPrint=1;var hwDocHWID="nord463";var hwDocTitle="Homocystinuria";var hwRank="1";var hwSectionHWID="nord463-Header";var hwSource="en-caQ2_05";var hwDocType="Nord"; National Organization for Rare Disorders, Inc. Homocystinuria Important It is possible that the main title of the report Homocystinuria is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report. Synonyms None Disorder Subdivisions None General Discussion Homocystinuria is a rare metabolic condition characterized by an excess of the compound homocystine in the urine. The condition may result from deficiency of any of several enzymes involved in the conversion of the essential amino acid methionine to another amino acid (cysteine)or, less commonly, impaired conversion of the compound homocysteine to methionine. Enzymes are proteins that accelerate the rate of chemical reactions in the body. Certain amino acids, which are the chemical building blocks of proteins, are essential for proper growth and development. Homocystinuria due to deficiency of cystathionine synthase is inherited as an autosomal recessive trait. The disorder results from changes (mutations) of a gene on the long arm (q) of chromosome 21 (21q22.3) that regulates the production of the CBS enzyme.

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