Yunis-Varon syndrome (YVS) is a severe autosomal recessive disorder characterized by skeletal defects, including cleidocranial dysplasia and digital anomalies, and severe neurologic involvement with neuronal loss. Enlarged cytoplasmic vacuoles are found in neurons, muscle, and cartilage. The disorder is usually lethal in infancy (summary by Campeau et al., 2013).

Brachydactyly type B2 (BDB2) is a subtype of brachydactyly characterized by hypoplasia/aplasia of distal phalanges in combination with distal symphalangism, fusion of carpal/tarsal bones, and partial cutaneous syndactyly (summary by Lehmann et al., 2007).

Cardiofacioneurodevelopmental syndrome (CFNDS) is characterized by microcephaly, midline facial defects, developmental delay, and cerebellar hypoplasia. Variable cardiac defects may be present, including atrioventricular canal and ventricular septal defects. Heterotaxy has also been reported (Harel et al., 2020).