Bartsocas-Papas syndrome-1 (BPS1) is an autosomal recessive disorder characterized by multiple popliteal pterygia, ankyloblepharon, filiform bands between the jaws, cleft lip and palate, and syndactyly. Early lethality is common, although survival into childhood and beyond has been reported (summary by Mitchell et al., 2012). Genetic Heterogeneity of Bartsocas-Papas Syndrome Bartsocas-Papas syndrome-2 (BPS2) is caused by mutation in the CHUK gene (600664). A less severe form of popliteal pterygium syndrome (PPS; 119500) is caused by mutation in the IRF6 gene (607199).

Ablepharon-macrostomia syndrome (AMS) is a congenital ectodermal dysplasia characterized by absent eyelids, macrostomia, microtia, redundant skin, sparse hair, dysmorphic nose and ears, variable abnormalities of the nipples, genitalia, fingers, and hands, largely normal intellectual and motor development, and poor growth (summary by Marchegiani et al., 2015).

Serine deficiency disorders include a spectrum of disease ranging from lethal prenatal-onset Neu-Laxova syndrome to serine deficiency with infantile, juvenile, or adult onset. Neu-Laxova syndrome is characterized by severe intrauterine growth deficiency, microcephaly, congenital bilateral cataracts, characteristic dysmorphic features, limb anomalies, and collodion-like ichthyosis. Infants are typically stillborn or die in early infancy. Infantile-onset serine deficiency is characterized by seizures, microcephaly, developmental delay, intellectual disability, and spastic quadriplegia. Individuals that present with juvenile-onset serine deficiency have seizures and many develop spastic quadriplegia. Adult-onset serine deficiency is characterized by progressive axonal polyneuropathy with ataxia and possible cognitive impairment.

The Cincinnati type of acrofacial dysostosis is a ribosomopathy characterized by a spectrum of mandibulofacial dysostosis phenotypes, with or without extrafacial skeletal defects (Weaver et al., 2015). In addition, a significant number of neurologic abnormalities have been reported, ranging from mild delays to refractory epilepsy, as well as an increased incidence of congenital heart defects, primarily septal in nature (Smallwood et al., 2023).

Serine deficiency disorders include a spectrum of disease ranging from lethal prenatal-onset Neu-Laxova syndrome to serine deficiency with infantile, juvenile, or adult onset. Neu-Laxova syndrome is characterized by severe intrauterine growth deficiency, microcephaly, congenital bilateral cataracts, characteristic dysmorphic features, limb anomalies, and collodion-like ichthyosis. Infants are typically stillborn or die in early infancy. Infantile-onset serine deficiency is characterized by seizures, microcephaly, developmental delay, intellectual disability, and spastic quadriplegia. Individuals that present with juvenile-onset serine deficiency have seizures and many develop spastic quadriplegia. Adult-onset serine deficiency is characterized by progressive axonal polyneuropathy with ataxia and possible cognitive impairment.