Early Genotype-Driven Diagnosis of Hermansky-Pudlak Syndrome Type 4 in a Child With Oculocutaneous Albinism: An Ophthalmic Case Report

Abstract

Hermansky-Pudlak syndrome (HPS) is a rare inherited multisystem condition characterized by oculocutaneous albinism, bleeding diathesis, and subtype-specific systemic complications, including pulmonary fibrosis and granulomatous colitis. Early diagnosis is essential because pulmonary involvement, particularly in HPS type 4, may be life-threatening. We report a boy who was first referred for ophthalmologic evaluation at seven weeks of age due to generalized hypopigmentation and congenital nystagmus. Examination revealed marked iris translucency, diffuse fundus hypopigmentation with prominent choroidal vasculature, pendular horizontal nystagmus, suspected esotropia, and hyperopia. Genetic testing was initiated at five months of age to determine the underlying cause of the oculocutaneous albinism, including possible syndromic causes. It identified biallelic variants in the HPS4 gene, confirming Hermansky-Pudlak syndrome type 4 at eight months of age. Multidisciplinary evaluation, including hematologic and pulmonary baseline assessments, was subsequently initiated. At the latest follow-up, at two years and five months of age, the patient remained clinically stable without evidence of pulmonary or gastrointestinal complications. Visual rehabilitation and early developmental support were implemented. This case underscores the critical role of early ophthalmologic recognition of oculocutaneous albinism in establishing the diagnosis of Hermansky-Pudlak syndrome. Timely genetic confirmation enables structured surveillance for pulmonary fibrosis and other systemic complications associated with HPS type 4.