MedGen

Belongs to the heterogeneous family of metabolic myopathies. It is characterised by progressive exercise intolerance manifesting in childhood, onset of sideroblastic anaemia around adolescence, lactic acidaemia and mitochondrial myopathy. Less than 10 cases have been described so far. A 656C-->T mutation in the nuclear pseudouridine synthase 1 gene (PUS1), localised to 12q24.33, has recently been identified in some patients. Deficient pseudouridylation of mitochondrial tRNAs may be responsible for the oxidative phosphorylation disorder. Transmission is autosomal recessive. [from SNOMEDCT_US]

Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by autonomic failure (cardiovascular and/or urinary), parkinsonism, cerebellar impairment and corticospinal signs with a median survival of 6-9 years. [from ORDO]

Retinoblastoma is a malignant tumor of the developing retina that occurs in children, usually before age five years. Retinoblastoma develops from cells that have cancer-predisposing variants in both copies of RB1. Retinoblastoma may be unifocal or multifocal. About 60% of affected individuals have unilateral retinoblastoma with a mean age of diagnosis of 24 months; about 40% have bilateral retinoblastoma with a mean age of diagnosis of 15 months. Heritable retinoblastoma is an autosomal dominant susceptibility for retinoblastoma. Individuals with heritable retinoblastoma are also at increased risk of developing non-ocular tumors. [from GeneReviews]