Constriction rings syndrome is a congenital limb malformation disorder with an extremely variable clinical presentation characterized by the presence of partial to complete, congenital, fibrous, circumferential, constriction bands/rings on any part of the body, although a particular predilection for the upper or lower extremities is seen. Phenotypes range from only a mild skin indentation to complete amputation of parts of the fetus (e.g. digits, distal limb). Compression from the rings may lead to edema, skeletal anomalies (e.g. fractures, foot deformities) and, infrequently, neural compromise.

MED12-related disorders include the phenotypes of FG syndrome type 1 (FGS1), Lujan syndrome (LS), X-linked Ohdo syndrome (XLOS), Hardikar syndrome (HS), and nonspecific intellectual disability (NSID). FGS1 and LS share the clinical findings of cognitive impairment, hypotonia, and abnormalities of the corpus callosum. FGS1 is further characterized by absolute or relative macrocephaly, tall forehead, downslanted palpebral fissures, small and simple ears, constipation and/or anal anomalies, broad thumbs and halluces, and characteristic behavior. LS is further characterized by large head, tall thin body habitus, long thin face, prominent nasal bridge, high narrow palate, and short philtrum. Carrier females in families with FGS1 and LS are typically unaffected. XLOS is characterized by intellectual disability, blepharophimosis, and facial coarsening. HS has been described in females with cleft lip and/or cleft palate, biliary and liver anomalies, intestinal malrotation, pigmentary retinopathy, and coarctation of the aorta. Developmental and cognitive concerns have not been reported in females with HS. Pathogenic variants in MED12 have been reported in an increasing number of males and females with NSID, with affected individuals often having clinical features identified in other MED12-related disorders.

Beta-ureidopropionase deficiency is a rare autosomal recessive inborn error of metabolism due to a defect in pyrimidine degradation. Less than 10 patients have been reported, and the phenotype can range from severe neurologic involvement with mental retardation and seizures to normal neurologic development (Yaplito-Lee et al., 2008).

Oculoectodermal syndrome (OES) is characterized by the association of epibulbar dermoids and aplasia cutis congenita. Affected individuals exhibit congenital scalp lesions which are atrophic, nonscarring, hairless regions that are often multiple and asymmetric in distribution, and may have associated hamartomas. Ectodermal changes include linear hyperpigmentation that may follow the lines of Blaschko and, rarely, epidermal nevus-like lesions. Epibulbar dermoids may be uni- or bilateral. Additional ocular anomalies such as skin tags of the upper eyelid and rarely optic nerve or retinal changes or microphthalmia can be present. Phenotypic expression is highly variable, and various other abnormalities have occasionally been reported, including growth failure, lymphedema, and cardiovascular defects, as well as neurodevelopmental symptoms such as developmental delay, epilepsy, learning difficulties, and behavioral abnormalities. Benign tumor-like lesions such as nonossifying fibromas of the long bones and giant cell granulomas of the jaws have repeatedly been observed and appear to be age-dependent, becoming a common manifestation in individuals aged 5 years or older (summary by Boppudi et al., 2016).

Bladder exstrophy and epispadias complex (BEEC) is an anterior midline defect with variable expression involving the infraumbilical abdominal wall including the pelvis, urinary tract, and external genitalia (Gearhart and Jeffs, 1998). BEEC is one of the most severe urologic birth defects because of its profound impact on continence, sexual function, and morbidity due to the effect of chronic and recurrent infections on renal function. The term 'exstrophy,' derived from the Greek work ekstriphein, which literally means 'turn inside out,' was first used by Chaussier in 1780. Martinez-Frias et al. (2001) emphasized that exstrophy of the cloaca and exstrophy of the bladder are 2 different expressions of a primary developmental field defect. Cloacal exstrophy is a feature of the OEIS (omphalocele-exstrophy-imperforate anus-spinal defects) complex (258040). Exstrophy of the cloaca includes the persistence and exstrophy of a common cloaca that receives ureters, ileum, and a rudimentary hindgut and is associated with failure of fusion of the genital tubercles and pubic rami, incomplete development of the lumbosacral vertebrae with spinal dysraphism, imperforate anus, cryptorchidism and epispadias in males and anomalies of the mullerian duct derivatives in females, and a wide range of urinary tract anomalies. Omphalocele is common, and most patients have a single umbilical artery. Reutter et al. (2016) reviewed the epidemiology, potential mechanisms, and animal models for BEEC. They described BEEC as a spectrum of component malformations of variable severity, including epispadias as the mildest phenotype and classic bladder exstrophy as the most common, with cloacal exstrophy representing the most severe form. In approximately one-third of cases, urologic malformations are present, including ectopic kidney, renal agenesis, and/or hydronephrosis. Other malformations involving the gastrointestinal, skeletal, spinal, and genitourinary systems, including cryptorchidism and ambiguous genitalia, are reported frequently. The authors noted that cloacal exstrophy is considered by some to have a different embryologic origin from classic bladder exstrophy.

Carey et al. (1978) gave the name OEIS complex to a combination of defects comprising omphalocele, exstrophy of the cloaca, imperforate anus, and spinal defects. This rare complex is thought to represent the most severe end of a spectrum of birth defects, the exstrophy-epispadias sequence, which, in order of increasing severity, includes phallic separation with epispadias, pubic diastasis, exstrophy of the bladder (600057), cloacal exstrophy, and OEIS complex. Very few instances of recurrence of anomalies in this cluster have been reported.