Unusually prominent horizontal gaze palsy in a case of Niemann-Pick type C disease
A 27-year-old lady, product of non-consanguineous marriage with uncomplicated birth history was apparently normal until 11 years of age. Symptoms started with worsening of school performance. The parents observed abnormal behavior in the form of restlessness, hallucinations, unprovoked episodes of screaming and crying, and decreased social interaction. Simultaneously, there was gradual onset of neurological symptoms accompanied by cognitive decline. The patient developed involuntary movements and abnormal posturing of limbs. Gradually progressive dysarthria and difficulty in walking due to clumsiness and impaired coordination interfered with patient’s ability to lead an independent life.\nFamily history records death of elder sibling of the patient at age of 28 years due to chronic disease. He had symptoms of progressive motor and cognitive decline and was diagnosed to have storage disorder following bone marrow examination. Unfortunately, clinical data in details was not available.\nOn examination, patient was conscious and oriented and the vitals were stable and initial survey revealed presence of generalized choreiform movements. Eye movement abnormality included both horizontal and down-gaze palsy []. Other findings included generalized dystonia with prominent tongue and limb dystonia []. Gait was characterized by short steppage, wide based with variable stride length []. Deep tendon reflexes were brisk in all four limbs.\nRoutine investigations were unremarkable. Complete blood counts including platelet count were normal and there was no evidence of organomegaly on ultrasound imaging. Magnetic resonance imaging of brain showed cortical atrophy, ex-vacuo dilatation of ventricles and prominence of sulci and gyri []. The infra-tentorial structures were relatively spared except for mild cerebellar atrophy. Bone marrow aspiration cytology demonstrated sea blue histiocytes implying lysosomal storage disorder [Figures ,]. No abnormality was seen on microscopic examination of skin biopsy specimen. Considering progressive neurodegenerative features along with characteristic bone marrow findings a provisional diagnosis of juvenile onset NPC was considered.