Permanent neonatal diabetes mellitus-pancreatic and cerebellar agenesis syndrome is characterized by neonatal diabetes mellitus associated with cerebellar and/or pancreatic agenesis.

In some cases, people with permanent neonatal diabetes mellitus also have certain neurological problems, including developmental delay and recurrent seizures (epilepsy). This combination of developmental delay, epilepsy, and neonatal diabetes is called DEND syndrome. Intermediate DEND syndrome is a similar combination but with milder developmental delay and without epilepsy.\n\nIndividuals with permanent neonatal diabetes mellitus experience slow growth before birth (intrauterine growth retardation). Affected infants have hyperglycemia and an excessive loss of fluids (dehydration) and are unable to gain weight and grow at the expected rate (failure to thrive).\n\nA small number of individuals with permanent neonatal diabetes mellitus have an underdeveloped pancreas. Because the pancreas produces digestive enzymes as well as secreting insulin and other hormones, affected individuals experience digestive problems such as fatty stools and an inability to absorb fat-soluble vitamins.\n\nPermanent neonatal diabetes mellitus is a type of diabetes that first appears within the first 6 months of life and persists throughout the lifespan. This form of diabetes is characterized by high blood sugar levels (hyperglycemia) resulting from a shortage of the hormone insulin. Insulin controls how much glucose (a type of sugar) is passed from the blood into cells for conversion to energy.

Any pancreatic agenesis in which the cause of the disease is a mutation in the PTF1A gene.

Holoprosencephaly-12 with or without pancreatic agenesis (HPE12) is a developmental disorder characterized by abnormal separation of the embryonic forebrain (HPE) resulting in dysmorphic facial features and often, but not always, impaired neurologic development. Most patients with this form of HPE also have congenital absence of the pancreas, resulting in early-onset type 1 diabetes mellitus and requiring pancreatic enzyme replacement. Other features may include hearing loss and absence of the gallbladder (summary by De Franco et al., 2019 and Kruszka et al., 2019). For a phenotypic description and a discussion of genetic heterogeneity of holoprosencephaly, see HPE1 (236100).