Mutations in PTRH2 cause novel infantile-onset multisystem disease with intellectual disability, microcephaly, progressive ataxia, and muscle weakness.

Objective: To identify the cause of a so-far unreported phenotype of infantile-onset multisystem neurologic, endocrine, and pancreatic disease (IMNEPD).

Methods: We characterized a consanguineous family of Yazidian-Turkish descent with IMNEPD. The two affected children suffer from intellectual disability, postnatal microcephaly, growth retardation, progressive ataxia, distal muscle weakness, peripheral demyelinating sensorimotor neuropathy, sensorineural deafness, exocrine pancreas insufficiency, hypothyroidism, and show signs of liver fibrosis.