Inborn errors of amino acid metabolism in north India.

We screened 2560 referred cases for inborn errors of amino acid metabolism by chemical tests and thin-layer chromatography of urine/plasma. In 62(2.4%) cases, eleven inherited Mendelian disorders of amino acids were identified. The four commonest disorders were homocystinuria, alcaptonuria, maple syrup urine disease and nonketotic hyperglycinaemia. Ornithinaemia was detected in two cases (0.08%), and phenylketonuria and cystinuria in two cases each (0.08%). Generalized hyperaminoacidurias were found in 90 (3.52%) subjects. The frequency pattern of the various amino acid disorders in North India was found to be remarkably different from that observed in the West.