A neurodegenerative disorder with early myoclonic encephalopathy, retinal pigmentary degeneration and nephronophthisis

A female case of developmental arrest, early-onset seizures, retinal pigmentary degeneration, progressive central nervous symptoms and peripheral neuropathy, associated with progressive renal dysfunction, anemia and nephrotic syndrome, was presented. Her epileptic syndrome was possibly an early myoclonic encephalopathy, though neonatal seizures were not evident. Serial cranial MRIs showed progressive brain atrophy and a white matter change. Neuropathological examination revealed a neurodegenerative disease mainly involving the white matter with olivopontocerebellar degeneration. She also had the nephronophthisis-medullary cystic disease complex and an early stage of focal segmental glomerulosclerosis. Her grandaunts had renal diseases, one of whom died of renal failure in adolescence, and her father showed cerebellar symptoms since the middle age. All possible metabolic studies were negative. This case is similar to Senior–Loken syndrome, but distinct in terms of the severe and progressive neurological symptoms, suggestive of a new malignant syndrome with some inherent metabolic derangement affecting both the nervous system and the kidneys.