GLIS3 and isolated cerebellar hypoplasia/agenesis: Other rare autosomal recessive forms of PNDM, which are associated with various organ impairments, have been genetically characterized and are easily differentiated from WRS: PDX1 mutations cause pancreas agenesis with additional exocrine pancreas deficiency [39], or a variant form with only neonatal diabetes [40]; PTF1A mutations cause pancreas and cerebellar agenesis [41]; GLIS3 mutations cause neonatal diabetes, congenital hypothyroidism and other clinical features [42].