Myelination disturbance in a patient with hyperuricemia and hyperserotoninemia combined with 18q deletion syndrome.

We previously reported a male patient with an 18q21.3 deletion, hyperuricemia and typical symptoms of the Lesch-Nyhan syndrome who lacked hypoxanthine-guanine-phosphoribosyl-transferase (HGPRT) deficiency. The patient developed progressive peripheral neuropathy in additon to his profound mental retardation and self-injurious behavior.