41. Homocystinuria homocystinuria,, Print this article, There are three types of homocystinuriaeach affecting a defect at a different step in the enzymatic pathway. http://www.amershamhealth.com/medcyclopaedia/Volume VII/HOMOCYSTINURIA.asp

Medcyclopaedia About Medcyclopaedia Amersham Health Search for: Type a word or a phrase. All forms of the word are searchable. Advanced search Browse entry words starting with: A B C D ... Other characters Try our Medcyclopaedia Premium Edition with added tools and functionality tailored to make your working day easier. The following tools are presently available: Expanded search *For Medical Professionals only, registration required Homocystinuria, metabolic disorder usually inherited as an autosomal recessive trait involving a congenital enzyme defect, cystathionine beta synthase. The resultant abnormal accumulation of homocysteine is converted to homocystine resulting in increased levels of homocystine in blood and urine. There are three types of homocystinuria each affecting a defect at a different step in the enzymatic pathway. Patients with type I homocystinuria often have mental retardation, are tall with long limbs, have inferior displacement of the lens and venous and arterial thromboembolic episodes. Radiographs show generalized osteoporosis with frequent pathological fractures and biconcavity of vertebral bodies, and enlarged carpal bones. They may also show arachnodactyly and scoliosis and pectus deformities. The skeletal changes and thrombotic episodes are absent in patients with type II or III homocystinuria. GL The Encyclopaedia of Medical Imaging Volume VII Welcome to Medcyclopaedia.

42. Eastern Mediterranean Health Journal, Vol. 5 No. 6, Classic Homocystinuria: Clin Classic homocystinuria clinical, biochemical and radiological observations,and therapeutic outcome of 24 Saudi patients Volume http://www.emro.who.int/Publications/EMHJ/0506/17.htm

Classic homocystinuria: clinical, biochemical and radiological observations, and therapeutic outcome of 24 Saudi patients Volume 5, Issue 6, 1999, Page 1196-1203 M.A. Al-Essa, M.S. Rashed and P.T. Ozand SUMMARY We considered the clinical, biochemical and radiological findings, and response to pyridoxine (vitamin B ) of 24 classic homocystinuric patients (15 females, 9 males) diagnosed at King Faisal Specialist Hospital and Research Centre. Common clinical findings included ectopia lentis (20 patients), skeletal system involvement (18 patients), vascular system involvement (9 patients) and mental retardation (all patients to varying degrees). A number of unusual findings were reported. The parents of 21 patients were first-degree relatives and 19 patients had at least one other family member affected by the same disease. Only 4 patients responded to pyridoxine; their methionine level decreased to almost normal range. Introduction Classic homocystinuria is the most common inborn error of methionine metabolism due to cystathionine b-synthase deficiency (CBS) [ ]. It leads to significant hypermethionaemia and increased plasma total homocystine (free, disulfide and protein-bound forms). There is also increased excretion of methionine and disulfides, homocystine and cysteine-homocysteine. Infants with this disorder have non-specific complaints. After the age of 3 years, sublaxation of the ocular lenses are is [

43. Homocystinuria homocystinuria There is considerable clinical heterogeneity in the classicalform of homocystinuria, due to deficiency of cystathionine asynthetase. http://www.sas-centre.org/genetic/genpages/aadisordhomocystinuria.html

Homocystinuria There is considerable clinical heterogeneity in the classical form of homocystinuria, due to deficiency of cystathionine a -synthetase. Symptoms include dislocation of the optic lens, mental retardation, osteoporosis, arterial or venous thrombosis, generalised convulsions and fits, but the severity of these varies considerably between patients. Enzyme Tests: Cystathionine b -synthetase is assayed to diagnose this disorder.

44. Health Library - Homocystinuria Search. homocystinuria. Infants born with homocystinuria may fail to grow andgain weight (failure to thrive) and may experience developmental delays. http://yourhealth.stlukesonline.org/library/healthguide/MedicalTests/topic.asp?h

45. Dr. Rose's Peripheral Brain--HOMOCYSTINURIA homocystinuria. Hyperhomocystinemia and homocystinuria result from various enzymedefects (homozygotes heterozygotes) or vitamin cofactor deficiencies; http://faculty.washington.edu/momus/PB/homocyst.htm

HOMOCYSTINURIA I. Biochemistry and pathophysiology Homocysteine is an intermediate in metabolism of methionine, an essential amino acid. Methionine serves as a methyl group donator for the synthesis of a variety of important biochemical intermediates (purines, thymine, creatine, etc.) In donating its methyl group it is converted to S-adenosyl-homocysteine which is then converted to homocysteineserves 2 functions: Can accept a methyl froup from folic acid to regenerate methionine (requires cobalamin) Can be converted to cystathionine and then to cysteine, another amino acid (requires pyridoxine) Hyperhomocysteinemia is strongly associated premature atherosclerosis and venous thromboembolism (Physician's Health Study, Framingham Heart Study) ; possibly also lens dislocation, skeletal abnormalities, and mental retardation II. Treatment to reduce plasma homocysteine concentrations and hopefully avoid complications

46. 1Up Health > Homocystinuria > Causes, Incidence, And Risk Factors Of Homocystinu Comprehesive information on homocystinuria . 1Up Health Diseases Conditions homocystinuria Causes, Incidence, and Risk Factors. http://www.1uphealth.com/health/homocystinuria_info.html

1Up Health Homocystinuria Alternative Medicine Clinical Trials ... Health Topics A-Z Search 1Up Health Homocystinuria Information Homocystinuria Causes, Incidence, and Risk Factors 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 (

47. 1Up Health > Health Links Directory > Conditions And Diseases: Neurological Diso Sites. Drkoop Medical Encyclopedia homocystinuria An in depth look at this disorder,including a definition, the causes and risk factors, symptoms, prevention http://www.1uphealth.com/links/metabolic-homocystinuria.html

Home Contact Us Privacy Caring For Your Well Being Alternative Medicine Clinical Trials Health News Poisons ... Health Topics A-Z Search 1Up Health Health Directory Addictions Alternative Animal ... Weight Loss By Demography Child Health Teen Health Men's Health Women's Health ... Metabolic : Homocystinuria Description See Related Categories Health: Conditions and Diseases: Genetic Disorders Health: Conditions and Diseases: Musculoskeletal Disorders: Connective Tissue Health: Conditions and Diseases: Rare Disorders Sites Drkoop: Medical Encyclopedia: Homocystinuria An in depth look at this disorder, including a definition, the causes and risk factors, symptoms, prevention, complications, prognosis, diagnosis and treatment. Homocystinuria An article about disorder, as to what it is, the symptoms, how it is inherited and the newborn screening program. NORD - Homocystinuria Offers alternative names, a general discussion and further resources. Pediatric Database A definition of homocystinuria, followed by epidemiology, pathogenesis, clinical features, investigations and management. Help build the largest human-edited directory on the web.

48. Homocystinuria Introduction. homocystinuria is an inborn error of metabolism in whichthe enzyme cystathionine synthase is deficient. 1,2 As in http://ortho.hyperguides.com/Tutorials/pediatric_ort/Homocystinuria/tutorial.asp

window.location="http://www.ortho.hyperguides.com/"; Homocystinuria Paul D. Sponseller, MD Introduction Clinical Features Radiographic Features Treatment ... References Introduction Homocystinuria is an inborn error of metabolism in which the enzyme cystathionine -synthase is deficient. As in the majority of enzyme deficiencies, homocystinuria is an autosomal recessive disorder because even half of the normal amount of enzyme can prevent the phenotype from developing. Cystathionine -synthase is responsible for the conversion of the amino acid methionine to cysteine. Homocysteine functions as an intermediary metabolite in the process and accumulates in the urine and blood when cystathionine -synthase is deficient. Other less common enzyme defects may also produce excessive amounts of homocysteine that result in homocystinuria. Accumulation of this intermediary results in a syndrome that has some resemblance to Marfan syndrome but also shows some major differences as well. Homocystinuria is a rare disorder with an incidence of approximately 1 in 300,000 births, whereas Marfan syndrome affects approximately 1 in 15,000. Clinical Features There are 2 major hypotheses to explain the development of the clinical features based on the known metabolic disturbance.

49. Pediatric Orthopedics- Homocystinuria homocystinuria. Paul D. Sponseller, MD Professor and Head of the Divisionof Pediatric Orthopedics The Johns Hopkins Hospital Baltimore, Maryland. http://ortho.hyperguides.com/Tutorials/pediatric_ort/Homocystinuria/default.asp

window.location="http://www.ortho.hyperguides.com/"; Homocystinuria Paul D. Sponseller, MD Professor and Head of the Division of Pediatric Orthopedics The Johns Hopkins Hospital Baltimore, Maryland

50. Health Library - Homocystinuria homocystinuria. None. General Discussion. homocystinuria is a rare metabolic conditioncharacterized by an excess of the compound homocystine in the urine. http://hvelink.saint-lukes.org/library/healthguide/IllnessConditions/topic.asp?h

51. Homocystinuria Facts homocystinuria Primary Defect Deficiency or absence of an enzyme necessary for thebreakdown of the amino acid methionine results in build up of methionine in 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. Prevalence estimates vary between 1 in 80,000 to 1 in 500,000. Possibly due to variation in sensitivity of the screening tests with age. If Untreated There is wide variation in clinical course for affected infants. Clinical features include: circulatory blood clotting (thromoembolism), 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.

52. Homocystinuria homocystinuria. Test. Bacterial inhibition assay to determine the levels of serummethionine. Genetics. Autosomal recessive; 150,000 to 1150,000. Pathology. http://gucfm.georgetown.edu/welchjj/netscut/genetics/Homocystinuria.html

Homocystinuria Test Bacterial inhibition assay to determine the levels of serum methionine Genetics Autosomal recessive 1:50,000 to 1:150,000 Pathology Excess methionine due to a disorder of the trans-sulfuration pathways that convert the sulfur atom of methionine into the sulfur atom of cystine. Most commonly a deficiency of the enzyme cystathionine B-synthetase. Diagnosis Marfanoid habitus, ectopia lentis (lens dislocation), glaucoma, cataracts, osteoporosis, high palatal arch, and muscle weakness with a shuffling gait. Consider in any child or young adult with thromboembolism affecting both the large and small arteries as well as the veins, particularly in association with developmental disabilities, mental retardation or skeletal findings. Treatment 50% respond to large doses of vitamin B6. Nonresponsive patients with cystathionine B-synthetase deficiency should be treated with a methionine-restricted cystine-supplemented diet. Acknowledgment This page is based on a 1998 presentation by Owen Rennert, Georgetown University Medical Center, Department of Pediatrics, Division of Genetics. Also see other Inborn Errors of Metabolism Genetics NetScut Home Please direct all comments to: Jack Welch, M.D., Ph.D.

53. Homocystinuria: Challenges In Diagnosis And Management November/December 1999, Volume 4, Number 8 557562 homocystinuria Challengesin diagnosis and management. Two patients with homocystinuria are discussed. http://www.pulsus.com/Paeds/04_08/garl_ed.htm

forgot your password? Case Report November/December 1999, Volume 4, Number 8: 557-562 Homocystinuria: Challenges in diagnosis and management J Garland, A Prasad, C Vardy, C Prasad Key Words: Attention deficit hyperactivity disorder; Cystathionine beta-synthase deficiency; Developmental delay; Homocystinuria; Lens dislocation Order Full Text -For a nominal fee order online and receive a copy of this article either by email, fax or mail Pdf Format - Registered users can view the complete article in Pdf format. REGISTERED USERS LOGIN REGISTER NOW! Des défis en matière de diagnostic et de traitement Order Full Text -For a nominal fee order online and receive a copy of this article either by email, fax or mail

54. Health Library - Homocystinuria Advanced Search. homocystinuria. Infants born with homocystinuria may fail to growand gain weight (failure to thrive) and may experience developmental delays. http://www.stjudemedicalcenter.org/library/healthguide/MedicalTests/topic.asp?hw

55. Health Library - Homocystinuria Advanced Search. homocystinuria. homocystinuria is a rare metabolic conditioncharacterized by an excess of the compound homocystine in the urine. http://www.stjudemedicalcenter.org/library/healthguide/IllnessConditions/topic.a

56. NEJM -- Coexistence Of Hereditary Homocystinuria And Factor V Leiden -- Effect O Original Article from The New England Journal of Medicine Coexistence ofHereditary homocystinuria and Factor V Leiden Effect on Thrombosis. http://content.nejm.org/cgi/content/short/334/12/763

HOME SEARCH CURRENT ISSUE PAST ISSUES ... HELP Previous Volume 334:763-768 March 21, 1996 Number 12 Next Hanna Mandel, M.D., Benjamin Brenner, M.D., Moshe Berant, M.D., Nurith Rosenberg, Ph.D., Naomi Lanir, Ph.D., Cornelis Jakobs, Ph.D., Brian Fowler, Ph.D., and Uri Seligsohn, M.D. Table of Contents Full Text of this article PDF of this article Related Letters to the Editor ... Related Articles in Medline Articles in Medline by Author: Mandel, H. Seligsohn, U. Medline Citation Anticoagulants/Thromboembolism ... Related Chapters at Harrison's Online ABSTRACT Background Venous and arterial thromboembolism occurs in only about one third of patients homozygous for homocystinuria, which suggests that other, contributory factors are necessary for the development of thrombosis in these patients. Factor V Leiden, an R506Q mutation in the gene coding for factor V, is the most common cause of familial thrombosis and could be a potentiating factor. Methods We determined activated partial-thromboplastin times in the presence and absence of activated protein C and tested for the factor V Leiden mutation in 45 members of seven unrelated consanguineous kindreds in which at least 1 member was homozygous for homocystinuria.

57. NEJM -- Platelet Survival And Morphology In Homocystinuria Due To Cystathionine Original Article from The New England Journal of Medicine Platelet survivaland morphology in homocystinuria due to cystathionine synthase deficiency. http://content.nejm.org/cgi/content/short/295/23/1283

HOME SEARCH CURRENT ISSUE PAST ISSUES ... HELP Previous Volume 295:1283-1286 December 2, 1976 Number 23 Next Platelet survival and morphology in homocystinuria due to cystathionine synthase deficiency ER Uhlemann, JH TenPas, AW Lucky, JD Schulman, SH Mudd, and NR Shulman Table of Contents Find Similar Articles in the Journal Notify a friend about this article Add to Personal Archive ... Alert me when this article is cited Articles in Medline by Author: Uhlemann, E. R. Shulman, N. R. Abstract In homocystinuria due to cystathionine synthase deficiency thromboembolism is a major cause of mortality and morbidity. Recent studies by others identified an abnormally shortened platelet survival and increased platelet vacuolization in patients with homocystinuria. When we studied six additional patients, however, we found the platelet survival to be within normal limits for each. The mean survival (+/-1 S.D.) was 9.75+/-0.94 days (normal, 9.27+/-1.06). In addition, platelets from five patients with homocystinuria and three obligate heterozygotes could not be distinguished from those of seven normal control subjects by electron microscopy. Specifically, no increased vacuolization was observed. Genetic heterogeneity, technical differences of differences in plasma homocystine concentrations could account for these descrepant results. The mechanism of thrombosis in homocystinuria remains an open question. This article has been cited by other articles: Monagle, P., Michelson, A. D., Bovill, E., Andrew, M. (2001). Antithrombotic Therapy in Children.

58. About Homocysteine, A Heart Disease Risk Marker, And Homocystinuria. Educational Site homocysteine its role as a heartdisease risk marker and factor in homocystinuria. http://www.homocysteine.net/pages/homocysteine/1/abouthcy.html

about homocysteine The interest in homocysteine has burgeoned during the last few years. Homocysteine is now considered a risk factor for several diseases, particularly cardiovascular disease where elevated levels of the amino acid is associated with increased risk of morbidity and mortality. The advent of simple assays has changed homocysteine measurement from a research tool to a standard and routine clinical test. The following sections will discuss the biochemical background as well as the association between elevated levels of Hcy and disease. The history of homocysteine Some biochemistry Why is homocysteine harmful? Why do homocysteine levels increase? ... Recommended reading The history of homocysteine Homocysteine was first described by Butz and du Vigneaud in 1932. Homocysteine is a sulphur-containing amino acid that is closely related to the essential amino acid methionine and to cysteine. An association between elevated homocysteine levels and human disease was first suggested in 1962 by Carson and Neil. They had found high homocysteine concentrations in the urine of some children with mental retardation. The elevated homocysteine levels in these patients were caused by severe enzyme defects blocking the homocysteine metabolism.

59. Papers On Homocysteine, Testing For Cardiovascular Disease And Homocystinuria . Educational Site Papers on homocysteine its use incardiovascular disease and homocystinuria testing. http://www.homocysteine.net/pages/publications/1/papers.html

papers Cardiology New data on homocysteine and stroke Birth defects and complications during pregnancy Male fertility and the homocysteine metabolism Neuropsychiatry Homocysteine levels and the risk of developing dementia Other clinical conditions Drugs causing homocysteine levels to increase ../js/page_head.js"

60. Homocystinuria Psychiatric manifestations of homocystinuria due to cystathionine betasynthasedeficiency prevalence, natural history, and relationship to neurologic http://www.truehope.com/disorders/ocd/3_1_4_4_11.asp

Site index Psychiatric manifestations of homocystinuria due to cystathionine beta-synthase deficiency: prevalence, natural history, and relationship to neurologic impairment and vitamin B6-responsiveness Am J Med Genet 1987 Apr;26(4):959-69 Abbott MH, Folstein SE, Abbey H, Pyeritz RE.

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