Lesch-Nyhan Disease a Treatable Mimicker of Dyskinetic Cerebral Palsy in Boys: Insights from an Indian Series of Six Cases with Report of Four Novel Variants

Background: HPRT1-related disorders are X-linked metabolic disorders of the purine pathway caused due to mutations in the hypoxanthine-guanine phosphoribosyl transferase (HPRT1) gene and present with features of dyskinetic cerebral palsy, self-mutilation/behavioral abnormality, and hyperuricemia in variable severity. Objective: Describe the clinical characteristics and treatment outcome of a series of 6 children with Lesch-Nyhan disease. Methods: Retrospective chart review from September 2022 to July 2024 of six molecularly confirmed cases of Lesch-Nyhan disease from India. Results: A total of 6 boys are described here. The mean age of onset was since birth, the age of diagnosis was 2 years 7 months, and the current age was 4 years 11 months. Features of developmental delay with motor predominance, dystonia, behavioral abnormality, and hyperuricemia (mean level 8.82 mg/dl) were seen in all. Self-mutilation was present in one while abnormal urine colour was noted in two cases. Routine metabolic tests were normal in all children. Seizures were noted in three children, with good response to therapy. The disease-causing mutation was identified in all: three missense variants and three loss of function variants: one each of nonsense, frameshift, and splice site. Treatment with Allopurinol resulted in a reduction of uric acid and only mild improvement in neurological features. Conclusion: The presentation of Lesch-Nyhan's disease usually mimics that of dyskinetic cerebral palsy. Normal imaging and increased uric acid give important clues for the diagnosis. Self-mutilation and abnormal urine color may not be always present. Early diagnosis helps in initiating treatment and preventing recurrence in the family.