Lesch-Nyhan Syndrome: A self mutilating behaviour

Causes of Lesch-Nyhan Syndrome

LNS is caused by mutations in the HPRT1 gene, located on the X chromosome. This gene is responsible for producing the HPRT enzyme, which plays a critical role in purine metabolism. The enzyme deficiency results in the overproduction of uric acid, leading to the hallmark symptoms of the syndrome.

Inheritance Pattern

• X-linked Recessive Disorder: As the gene is located on the X chromosome, males are predominantly affected. Females are usually carriers and rarely show symptoms.

Symptoms of Lesch-Nyhan Syndrome

Physical Symptoms

1. Elevated Uric Acid Levels:

   • Gouty arthritis

   • Kidney stones

2. Neurological Abnormalities:

   • Hypotonia (low muscle tone) in infancy

   • Spasticity (stiff or tight muscles)

   • Chorea (involuntary jerky movements)

3. Growth Delays: Reduced growth rates are common.

Behavioral Symptoms

• Self-Injurious Behavior:

  • Biting fingers, lips, and cheeks

  • Head banging

• Aggression or emotional instability

Cognitive Impairment

While many individuals with LNS have normal intelligence, some may experience mild to moderate intellectual disabilities.

Diagnosis of Lesch-Nyhan Syndrome

Diagnosing LNS involves a combination of clinical evaluation, family history, and laboratory tests.

Diagnostic Methods

1. Blood and Urine Tests: To detect elevated uric acid levels.

2. Enzyme Assay: To measure HPRT enzyme activity in blood or skin cells.

3. Genetic Testing: Confirms mutations in the HPRT1 gene.

Differential Diagnosis

Conditions such as cerebral palsy or other metabolic disorders may mimic LNS symptoms and should be ruled out.

Treatment Options for Lesch-Nyhan Syndrome

Medical Management

• Allopurinol: Reduces uric acid production and prevents gout and kidney stones.

• Medications for Muscle Spasticity: Baclofen or benzodiazepines may help alleviate stiffness.

Behavioral Management

• Behavioral therapy and protective measures can minimize self-injury. Dental guards are often used to prevent damage caused by biting.

Supportive Care

1. Physical Therapy: To manage spasticity and improve mobility.

2. Nutritional Support: To address feeding difficulties and ensure proper growth.

Experimental Therapies

• Gene therapy and enzyme replacement therapy are being explored as potential future treatments.

Prognosis

Although there is no cure for LNS, early diagnosis and appropriate interventions can improve quality of life. Most individuals require lifelong medical care and support.

Conclusion

Lesch-Nyhan Syndrome is a complex disorder requiring a multidisciplinary approach to management. While current treatments focus on symptom relief, advancements in genetic research hold promise for more effective therapies in the future. Early intervention and support are essential for enhancing the lives of individuals with LNS and their families.