Hereditary nephrogenic diabetes insipidus (NDI) is characterized by inability to concentrate the urine, which results in polyuria (excessive urine production) and polydipsia (excessive thirst). Affected untreated infants usually have poor feeding and failure to thrive, and rapid onset of severe dehydration with illness, hot environment, or the withholding of water. Short stature and secondary dilatation of the ureters and bladder from the high urine volume is common in untreated individuals.

Hereditary nephrogenic diabetes insipidus (NDI) is characterized by inability to concentrate the urine, which results in polyuria (excessive urine production) and polydipsia (excessive thirst). Affected untreated infants usually have poor feeding and failure to thrive, and rapid onset of severe dehydration with illness, hot environment, or the withholding of water. Short stature and secondary dilatation of the ureters and bladder from the high urine volume is common in untreated individuals.

The TP63-related disorders comprise six overlapping phenotypes: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome (which includes Rapp-Hodgkin syndrome). Acro-dermo-ungual-lacrimal-tooth (ADULT) syndrome. Ectrodactyly, ectodermal dysplasia, cleft lip/palate syndrome 3 (EEC3). Limb-mammary syndrome. Split-hand/foot malformation type 4 (SHFM4). Isolated cleft lip/cleft palate (orofacial cleft 8). Individuals typically have varying combinations of ectodermal dysplasia (hypohidrosis, nail dysplasia, sparse hair, tooth abnormalities), cleft lip/palate, split-hand/foot malformation/syndactyly, lacrimal duct obstruction, hypopigmentation, hypoplastic breasts and/or nipples, and hypospadias. Findings associated with a single phenotype include ankyloblepharon filiforme adnatum (tissue strands that completely or partially fuse the upper and lower eyelids), skin erosions especially on the scalp associated with areas of scarring, and alopecia, trismus, and excessive freckling.

Urofacial syndrome (UFS) is characterized by prenatal or infantile onset of urinary bladder voiding dysfunction, abnormal facial movement with expression (resulting from abnormal co-contraction of the corners of the mouth and eyes), and often bowel dysfunction (constipation and/or encopresis). Bladder voiding dysfunction increases the risk for urinary incontinence, megacystis, vesicoureteric reflux, hydroureteronephrosis, urosepsis, and progressive renal impairment. In rare instances, an individual who has (a) a molecularly confirmed diagnosis and/or (b) an affected relative meeting clinical diagnostic criteria manifests only the characteristic facial features or only the urinary bladder voiding dysfunction (not both). Nocturnal lagophthalmos (incomplete closing of the eyes during sleep) appears to be a common and significant finding.

ACTG2 visceral myopathy is a disorder of smooth muscle dysfunction of the bladder and gastrointestinal system with phenotypic spectrum that ranges from mild to severe. Bladder involvement can range from neonatal megacystis and megaureter (with its most extreme form of prune belly syndrome) at the more severe end, to recurrent urinary tract infections and bladder dysfunction at the milder end. Intestinal involvement can range from malrotation, neonatal manifestations of microcolon, megacystis microcolon intestinal hypoperistalsis syndrome, and chronic intestinal pseudoobstruction (CIPO) in neonates at the more severe end to intermittent abdominal distention and functional intestinal obstruction at the milder end. Affected infants (with or without evidence of intestinal malrotation) often present with feeding intolerance and findings of non-mechanical bowel obstruction that persist after successful surgical correction of malrotation. Individuals who develop manifestations of CIPO in later childhood or adulthood often experience episodic waxing and waning of bowel motility. They may undergo frequent abdominal surgeries (perhaps related to malrotation or adhesions causing mechanical obstruction) resulting in resection of dilated segments of bowel, often becoming dependent on total parenteral nutrition (TPN).

Visceral myopathy-2 (VSCM2) is characterized by gastrointestinal symptoms resulting from intestinal dysmotility and paresis, including abdominal distention, pain, nausea, and vomiting. Some patients exhibit predominantly esophageal symptoms, with hiatal hernia and severe reflux resulting in esophagitis and stricture, whereas others experience chronic intestinal pseudoobstruction. Bladder involvement resulting in megacystis and megaureter has also been observed and may be evident at birth (Dong et al., 2019; Gilbert et al. (2020)).

Megacystis-microcolon-intestinal hypoperistalsis syndrome-2 (MMIHS2) is characterized by prenatal bladder enlargement, neonatal functional gastrointestinal obstruction, and chronic dependence on total parenteral nutrition and urinary catheterization. The majority of cases have a fatal outcome due to malnutrition and sepsis, followed by multiorgan failure (summary by Wang et al., 2019). For a discussion of genetic heterogeneity of MMIHS, see 249210.

Megacystis-microcolon-intestinal hypoperistalsis syndrome-4 (MMIHS4) is a severe early-onset disorder characterized by impaired smooth muscle contractility in the bladder and intestines (Kandler et al., 2020). For a discussion of genetic heterogeneity of MMIHS, see 249210.

Megacystis-microcolon-intestinal hypoperistalsis syndrome-5 (MMIHS5) is a form of visceral myopathy characterized by significant inter- and intrafamilial variability, with the most severely affected patients exhibiting prenatal bladder enlargement, intestinal malrotation, neonatal functional gastrointestinal obstruction, and chronic dependence on total parenteral nutrition (TPN) and urinary catheterization (Wangler et al., 2014). For a general phenotypic description and discussion of genetic heterogeneity of MMIHS, see MMIHS1 (249210).