DISCUSSION
So far more than 7,000 genetic disorders have been identified. Approximately I in 1500 children are born with defective enzymes resulting in inborn errors of metabolism (7). Earlier studies have reported cases
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of hyperprolinemia in association with other disorders such as renal diseases (1), aniridia and ocular dystrophy (2) and mental retardation and convulsions (3,4). From India, the first case of type I hyperprolinemia was reported recently from Bangalore, a city in South India by Shivananda et al. (2000) (5) in an individual with mental retardation and convulsions.
Reports on hyperprolinuria with hyperhydroxyprolinuda are very rare. As early as in 1968, Rokkens and Loken (8) from Europe reported a case of renal dysplasia and mental retardation, who had an increased excretion of proline and hydroxyproline in urine, while plasma levels of these amino acids were normal. This patient died at the age of 6 years and 5 months. In our screening programme, we have detected a similar case for the first time in South India.