aminoacidurias lecture15.09.10

AMINOACIDOPATHIES – CLASSIFICATION AND DIAGNOSIS : 

AMINOACIDOPATHIES – CLASSIFICATION AND DIAGNOSIS Dr. Hariharan, II yr MD biochemistry 15.09.2010 Moderator - Dr.Ragavendran, Professor, Dept of pediatrics Co-ordinator- Dr. Ashok kumar, MD, DLO, Assistant Professor, Dept of Biochemistry

History : 

History 1908- Garrod – alkaptonuria, benign pentosuria, albinism, cystinuria Følling’s -phenylketonuria (PKU) in 1934 Harry Harris-1955-starch gel electrophoresis-demonstrated of a large number of protein polymorphisms in humans discovery of PKU sparked the search for other clinically significant inborn errors of metabolism> 500 disorders

What can go wrong? : 

A A B C D negative E F Apoenzyme + cofactor What can go wrong?

Incidence of aminoacidurias : 

Incidence of aminoacidurias

Inheritance : 

Inheritance

Urea cycle defects : 

Urea cycle defects NH3 + H20 + CO2 Carbamoyl phosphate Hyperammonemia I Hyperammonemia II OTC Urea citrullinemia Argino succinic aciduria

Branched chain aminoacidurias : 

Branched chain aminoacidurias Isovaleryl coA dehydrogenase Alpha ketoacid dehydrogenase

Homocystinurias : 

Homocystinurias Homocystinuria 1 Cystathionine Homocystinuria 3 Homocystinuria 2 N5-N10 MTHF transferase MTHFR

Phenylalanine and tyrosine : 

Phenylalanine and tyrosine Tyrosinemia 2 Tyrosinemia 1 Alkaptonuria PKU hydroxylase Amino transferase Hydrolase

Laboratory investigation : 

Laboratory investigation Blood Electrolytes, glucose, ammonia URINE- Ferric chloride test- alkaptonuria Cyanide nitroprusside -S- DNPH-MSUD Benedict’s test -alkaptonuria Thin layer chromatography Tandem mass spectrometry

Confirmatory tests : 

Confirmatory tests PKU- plasma phenyl alanine levels, urinary metabolites Tyrosinemias-plasma tyrosine levels, urine- succinyl acetone Homocystinurias- increased plasma methionine & homocysteine. Low cystine MSUD- increased leucine, isoleucine, valine Urea cycle defects- ammonia, glutamine, alanine, other aminoacids

Collection of urine sample : 

Collection of urine sample

Screening in newborn : 

Screening in newborn Guthrie’s test- earliest Various procedures in varying countries

References : 

References Vasudevan- textbook of biochemistry A clinical guide to inherited metabolic disorders- Clarke Pubmed.com Wikipedia.org

Slide 18: 

Thank you