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 high-frequency 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.