HxFyS

HxFyS is a rare genetic disorder that affects the body's ability to metabolize purines. Purines are essential building blocks of DNA and RNA, and they are also involved in energy transfer within cells. In individuals with HxFyS, a deficiency in the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT1) leads to an accumulation of uric acid in the blood and tissues.

The HPRT1 enzyme is crucial for the salvage pathway of purine metabolism, which recycles purine bases. When HPRT1 is deficient, the body cannot effectively reuse these bases, leading to increased de novo synthesis of purines and a subsequent overproduction of uric acid. This condition is inherited in an X-linked recessive pattern, meaning it primarily affects males.

Symptoms of HxFyS can vary in severity and typically manifest in early childhood. Common features include neurological impairments such as intellectual disability, self-mutilating behaviors (biting of fingers and lips), spasticity, and involuntary movements (dystonia and chorea). Kidney problems, including kidney stones and gouty arthritis due to uric acid crystal deposition, are also characteristic.

Diagnosis of HxFyS is usually made through biochemical testing to measure HPRT1 enzyme activity and genetic testing to identify mutations in the HPRT1 gene. There is no cure for HxFyS, but management focuses on alleviating symptoms. Medications like allopurinol can help reduce uric acid levels and prevent kidney complications. Physical and occupational therapy can assist with motor impairments, and behavioral interventions are used to manage self-mutilating behaviors. Early diagnosis and consistent management are important for improving the quality of life for affected individuals.