Lesch-Nyhan disease is a genetic disorder which causes neurological and behavioral abnormalities. Overproduction of uric acid is another clinical feature associated with this disease. The disease is also known as Lesch-Nyhan Syndrome, HPRT Hypoxanthine Phosphoribosyl Transferase) deficiency syndrome and X-linked hyperuricemia. Michael Lesch and William Nyhan provided the first detailed clinical description of Lesch-Nyhan disease in 1964.
Gene and Locus and Chromosome location
The disease is associated with X-chromosome. It involves mutation of the HPRT gene located at 26.2 and 26.3 positions in the q arm of X-chromosome.
Inheritance pattern
Lesch-Nyhan disease is X-linked recessive disorder. It is common in …show more content…
The HPRT1 gene codes for an enzyme called hypoxanthine phosphoribosyl transferase 1. This enzyme is responsible for recycling of purines. The recycling of purines ensures that cells have enough amount of purines for the synthesis of nucleotides (DNA & RNA). Mutation in HPRT1 gene causes a shortage or complete absence of hypoxanthine phosphoribosyl transferase 1. In this condition, purines are broken down but not recycled causing an increase in the levels of uric …show more content…
HPRT enzyme assay is most readily accomplished using erythrocyte in anticoagulants or dried blood spots on filter paper. Measurement of HPRT enzyme activity for carrier detection is technically demanding [Puig et al 1998]. Molecular genetic testing provides an alternative strategy to HPRT enzyme assay, in which the sequence of DNA of an individual is analyzed for the mutation in the HPRT gene on X chromosome.
Treatment
Primarily, overproduction of uric acid must be controlled to prevent abnormalities. It can be done by two ways, by inhibiting the metabolism of hypoxanthine and xanthine to uric acid with allopurinol and by generous hydration. Allopurinol effectively limits hyperuricemia. Febuxostat is an option for patients who cannot tolerate allopurinol. Benzodiazepines, such as diazepam or alprazolam, can reduce the severity of neurological abnormalities. Antispasticity agents such as baclofen can also be helpful in controlling muscle spasm.
Management of the behavioral problems, particularly the self-injurious behavior, can be very difficult. In general, behavioral problems are best managed with a combination of behavioral-modification techniques and medication. Removal of teeth may be the only procedure for preventing self-injurious