1. HomocystineuriaA relatively rare condition caused by cystathionine synthetase deficiency in the liver.It is transmitted by AR mode. Homocystine level in plasma is increased and excreted in urine(detected by cyanide nitropruside test).The main clinical manifestations in the homozygous individual include: Subluxation in the lens. Recurrent thromboembolism. Convulsions. Osteoporosis. Intellectual impairment. Long extremities and digits.Treatment: Methionine restriction + Pyridoxine + folic acid. Maple syrup urine disease (MSUD)A rare AR disorder in which affected patients have elevated level of Leucine , Isolucine & Valinein urine , Serum & CSF.Affected babies are born normal, but within the first week symptoms like poor feeding,lethargy, vomiting , convulsion & spasticity. Death ultimately occurs during infancy.Ferric chloride test on urine may help it detect giving a blue color.Traetment : not very successful & is by feeding the patient a synthetic mixture with minimalLucine, Isolucine & Valine + B1. 1

2. Urea cycle disorder (UCD)Ammonia (produced by catabolism of aminoacids) is converted to urea through 5 stages. Eachstage is controlled by an enzyme, defect of which result in different aminoacidopathy such as: Hyper ammonemia. Arginiosuccenic acidurea. Citrollinemia. Hyperargininemia.Whichever is the case, affected patients are intolerant for protein & show features like:Vomiting, Irritability, Lethargy, Coma, and Ataxia & Convulsion.Blood urea is low to normal with elevation of the precursors.Treatment: is not very successful & is by frequent protein free feeds. CystinosisA rare A.R. disorder, the defect in which is not quite clear.Affected children will show symptoms at 4 6 months of age, features include; Fair complexion & blond hair. Retinal depigmented patches. Polyuria. Polydypsia. Dehydration. Failure to thrive. Phosphaturia & vit. D resistant rickets. Deposition of cystine crystal in the cornea (detected by slit lamp exam), in bone marrow & leukocytes. 2

3. Progressive glomerular damage.Traetment: There is no specific therapy, large doses of Vit. D & phosphate. Anabolic steroid may help growth. Low thionine & cystine diet. Cystinuria An A.R disorder with a defect of transport of Cystine across both renal tubular cell and intestine. There is a selective increase in renal excretion of Cystine, Lysine, Arginine & Ornithine. Cystine (among these excreted aminoacids) is responsible for causing frequent renal stone formation.Treatment: Adequate hydration & alkalinization of urine as Cystine crystal are soluble in alkaline urine. D- penicillamine (forms a water soluble combination). Low methionine food. Captopril produces marked reduction in Cystine. Hartnup diseaseAn A.R disorder caused by defect in tryptophan absorption.Affected children may remain asymptomatic.Severe forms cause intermittent ataxia, pellagra like photosensitive rash, diarrhea, dementia &immotional labiality. 3

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