AN X-LINKED SYNDROME CHARACTERISED BY HYPERURICAEMIA, DEAFNESS, AND NEURODEVELOPMENTAL ABNORMALITIES

Purine overproduction, with normal levels of the purine salvage enzymes, has been found in a 3-year-old boy and his mother. Both have highfrequency hearing loss from infancy. The child is hypotonic and shows locomotor delay. Two male siblings with similar neurodevelopmental problems died in early childhood. Biochemical studies suggest a combined syndrome associated with a superactive PP-ribose-P synthetase which in its severest form may produce neurodevelopmental complications, as well as uric-acid overproduction. Severe depletion of erythrocyte nicotinamide adenine dinucleotide and guanosine triphosphate appears to be associated with the neurological abnormalities and may be useful in diagnosis.