Atypical juvenile neuronal ceroid lipofuscinosis: A report of three cases
An 11-year-10-month-old Caucasian boy with normal perinatal and neurodevelopmental history was referred to us with 3-year history of progressive visual loss and visual hallucinations. His symptoms started with difficulty in reading, worsening handwriting, and flashes of lights in both eyes (BE). He gave us a description and consistently drew figures, which he appeared to be seeing in front of his eyes. The figures had a red border with circles and lines criss-crossing the circles.\nThe VA at first presentation was 6/60 in BE when he was 10 years. At last follow-up at 13, VA was 6/60 in right eye (RE) and 3/60 in left eye (LE). He was able to detect colours but could not read any letters. Visual field did not show specific defect. Optic disc and neurological examinations were unremarkable at last follow-up.\nVEP of BE were delayed while ERG was normal at 12 years. MRI and EEG were normal. Blood film showed no lymphocyte vacuolation. However, electron microscopy (EM) of buffy coat showed rare, membrane bound, electron dense, granular material associated with a lipid droplet in the cytoplasm of lymphocytes. PPT activity was low measuring 2.2 nmol/hr/mg protein and normal TPP-I. Molecular genetic analysis of exon 1-9 of CLN1 gene showed that he was heterozygote for p.Cys96Tyr and p.Arg151X mutations.\nA diagnosis of milder form of INCL (CLN1) was made. At his last neurology follow-up at 13 years, his vision remained poor. He had developed behavioral and cognitive problems. He had not developed seizures or motor difficulties.