HGPRT and APRT activities in hemolysates during the first year of life

Early postnatal diagnosis of hypoxanthine guanine phosphoribosyl transferase (HGPRT) deficiency is frequently performed nowadays during the first year of life. The clinical expression of HGPRT deficiency is usually manifested by a variable psychomotor retardation between 6 and 12 months of age and may result in a variety of clinical syndromes, with markedly different neurological manifestations or even no neurological symptoms. At this age, or even earlier, parents or pediatricians may seek medical attention because they notice some developmental retardation in their child, sandy or coloured urine in the diapers, and/or because hyperuricemia and/or hyperuricosuria was discovered incidentally. Also babies belonging to a family with some male affected by this enzyme deficiency may seek early diagnosis (1).