Title : Unravelling an ABHD12 mutation: a genetically confirmed case of PHARC syndrome
Abstract:
Purpose: The purpose of this case report is to highlight the clinical heterogeneity and diagnostic challenges of PHARC syndrome, a rare autosomal recessive neurodegenerative disorder caused by ABHD12 gene mutations. By presenting this report, we highlight the value of multisystem evaluation and molecular testing in diagnosing PHARC syndrome.
Method: We report the case of a 29-year-old male who presented with complaints of night blindness. He had a history of bilateral cataract extraction at the age of 17 and progressive hearing loss, for which he underwent cochlear implantation at 25 years of age. Fundus examination revealed features consistent with retinitis pigmentosa sine pigmento in both eyes, supported by characteristic findings on fundus autofluorescence imaging. Central nervous system examination was normal. Nerve conduction velocity studies, however, demonstrated sensorimotor polyneuropathy in all four limbs, despite the patient being clinically asymptomatic. Genetic analysis identified a pathogenic homozygous mutation in the ABHD12 gene, confirming the diagnosis of PHARC syndrome.
Discussion: This case highlights the diagnostic challenges of PHARC syndrome, which may mimic other hereditary syndromes such as Usher syndrome and Refsum disease. Early identification through genetic and clinical assessment, supported by patient counselling, appropriate symptomatic management, and consistent follow-up, is vital for effective monitoring of disease progression.
Conclusion: PHARC syndrome should be considered among the differential diagnoses in patients presenting with hearing loss and visual symptoms. This case emphasizes the importance of a multidisciplinary approach and genetic confirmation in the diagnosis of rare neurodegenerative disorders.
