Mitochondrial Myopathy and Sideroblastic Anemia 1 (PUS1)

Mitochondrial myopathy and sideroblastic anemia 1 is an autosomal recessive disorder caused by pathogenic variants in the gene PUS1. While this disorder has been reported in patients of different ethnicities, a founder effect has been identified in the Sephardic Jewish population from Iran. Onset of clinical symptoms is in infancy or childhood. Clinical features include muscle weakness, buildup of lactic acid in the muscles, and sideroblastic anemia, a form of anemia where red blood cells do not develop properly resulting in inefficient oxygen transport. Early onset forms may present with failure to thrive and developmental delay or intellectual disability, whereas later-onset forms may present with muscle weakness. The disease is typically fatal in childhood or adolescence. No genotype-phenotype correlation has been reported, and therefore the severity of the disease cannot be predicted based on genotype.

For information about carrier frequency and residual risk, please see the residual risk table.