OBAIRH is an autosomal recessive endocrine disorder characterized by early-onset obesity due to severe hyperphagia, pigmentary abnormalities, mainly pale skin and red hair, and secondary hypocortisolism. In the neonatal period, affected individuals are prone to hypoglycemia, hyperbilirubinemia, and cholestasis that may result in death if not treated. The disorder results from mutation in the POMC gene, which encodes a preproprotein that is processed into a range of bioactive peptides, including alpha-melanocyte-stimulating hormone (MSH) and ACTH (summary by Kuhnen et al., 2016 and Clement et al., 2008).

Acrodysostosis-1 (ACRDYS1) is a form of skeletal dysplasia characterized by short stature, severe brachydactyly, facial dysostosis, and nasal hypoplasia. Affected individuals often have advanced bone age and obesity. Laboratory studies show resistance to multiple hormones, including parathyroid, thyrotropin, calcitonin, growth hormone-releasing hormone, and gonadotropin (summary by Linglart et al., 2011). However, not all patients show endocrine abnormalities (Lee et al., 2012). Genetic Heterogeneity of Acrodysostosis See also ACRDYS2 (614613), caused by mutation in the PDE4D gene (600129) on chromosome 5q12.