The 17q12 recurrent deletion syndrome is characterized by variable combinations of the three following findings: structural or functional abnormalities of the kidney and urinary tract, maturity-onset diabetes of the young type 5 (MODY5), and neurodevelopmental or neuropsychiatric disorders (e.g., developmental delay, intellectual disability, autism spectrum disorder, schizophrenia, anxiety, and bipolar disorder). Using a method of data analysis that avoids ascertainment bias, the authors determined that multicystic kidneys and other structural and functional kidney anomalies occur in 85% to 90% of affected individuals, MODY5 in approximately 40%, and some degree of developmental delay or learning disability in approximately 50%. MODY5 is most often diagnosed before age 25 years (range: age 10-50 years).

The Martinez-Frias syndrome is characterized by pancreatic hypoplasia, intestinal atresia, and gallbladder aplasia or hypoplasia, with or without tracheoesophageal fistula. There is considerable phenotypic overlap between Martinez-Frias syndrome and Mitchell-Riley syndrome (MTCHRS; 615710), the latter being characterized by neonatal diabetes in addition to the features of the Martinez-Frias syndrome, but without tracheoesophageal fistula (Smith et al., 2010).

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

Neonatal diabetes mellitus with congenital hypothyroidism (NDH) syndrome is characterized by intrauterine growth retardation and onset of nonimmune diabetes mellitus within the first few weeks of life. Other features include renal parenchymal disease, primarily renal cystic dysplasia, and hepatic disease, with hepatitis in some patients and hepatic fibrosis and cirrhosis in others. Facial dysmorphism, when present, consistently involves low-set ears, epicanthal folds, flat nasal bridge, long philtrum, and thin upper lip. Most patients exhibit developmental delay (Dimitri et al., 2015).

The histiocytosis-lymphadenopathy plus syndrome comprises features of 4 histiocytic disorders previously thought to be distinct: Faisalabad histiocytosis (FHC), sinus histiocytosis with massive lymphadenopathy (SHML), H syndrome, and pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome (PHID). FHC was described as an autosomal recessive disease involving joint deformities, sensorineural hearing loss, and subsequent development of generalized lymphadenopathy and swellings in the eyelids that contain histiocytes (summary by Morgan et al., 2010). SHML, or familial Rosai-Dorfman disease, was described as a rare cause of lymph node enlargement in children, consisting of chronic massive enlargement of cervical lymph nodes frequently accompanied by fever, leukocytosis, elevated erythrocyte sedimentation rate, and polyclonal hypergammaglobulinemia. Extranodal sites were involved in approximately 25% of patients, including salivary glands, orbit, eyelid, spleen, and testes. The involvement of retropharyngeal lymphoid tissue sometimes caused snoring and sleep apnea (summary by Kismet et al., 2005). H syndrome was characterized by cutaneous hyperpigmentation and hypertrichosis, hepatosplenomegaly, heart anomalies, and hypogonadism; hearing loss was also found in about half of patients, and many had short stature. PHID was characterized by predominantly antibody-negative insulin-dependent diabetes mellitus associated with pigmented hypertrichosis and variable occurrence of other features of H syndrome, with hepatosplenomegaly occurring in about half of patients (Cliffe et al., 2009). Bolze et al. (2012) noted that mutations in the SLC29A3 gene (612373) had been implicated in H syndrome, PHID, FHC, and SHML, and that some patients presented a combination of features from 2 or more of these syndromes, leading to the suggestion that these phenotypes should be grouped together as 'SLC29A3 disorder.' Bolze et al. (2012) suggested that the histologic features of the lesions seemed to be the most uniform phenotype in these patients. In addition, the immunophenotype of infiltrating cells in H syndrome patients was shown to be the same as that seen in patients with the familial form of Rosai-Dorfman disease, further supporting the relationship between these disorders (Avitan-Hersh et al., 2011; Colmenero et al., 2012).

Mitchell-Riley syndrome is characterized by neonatal diabetes, pancreatic hypoplasia, intestinal atresia, and gallbladder aplasia or hypoplasia. There is considerable phenotypic overlap between Mitchell-Riley syndrome and Martinez-Frias syndrome (601346), the latter being characterized by the features of the Mitchell-Riley syndrome except for neonatal diabetes, and including tracheoesophageal fistula in some patients (Smith et al., 2010).

A 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\nIn 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\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.

A rare, syndromic diabetes mellitus characterized by partial pancreatic agenesis, diabetes mellitus, and heart anomalies (including transposition of the great vessels, ventricular or atrial septal defects, pulmonary stenosis, or patent ductus arteriosis).

Pancreatic agenesis-2 (PAGEN2) is an autosomal recessive disorder characterized by neonatal-onset diabetes mellitus and pancreatic exocrine deficiency (Weedon et al., 2014). For a discussion of genetic heterogeneity of pancreatic agenesis, see PAGEN1 (260370).

Severe congenital liver disease (SCOLIV) is an autosomal recessive disorder characterized by the onset of progressive hepatic dysfunction usually in the first years of life. Affected individuals show feeding difficulties with failure to thrive and features such as jaundice, hepatomegaly, and abdominal distension. Laboratory workup is consistent with hepatic insufficiency and may also show coagulation defects, anemia, or metabolic disturbances. Cirrhosis and hypernodularity are commonly observed on liver biopsy. Many patients die of liver failure in early childhood (Moreno Traspas et al., 2022).