Simpson-Golabi-Behmel syndrome type 1 (SGBS1) is characterized by pre- and postnatal macrosomia; distinctive craniofacial features (including macrocephaly, coarse facial features, macrostomia, macroglossia, and palate abnormalities); and, commonly, mild-to-severe intellectual disability with or without structural brain anomalies. Other variable findings include supernumerary nipples, diastasis recti / umbilical hernia, congenital heart defects, diaphragmatic hernia, genitourinary defects, and gastrointestinal issues. Skeletal anomalies can include vertebral fusion, scoliosis, rib anomalies, and congenital hip dislocation. Hand anomalies can include large hands and postaxial polydactyly. Affected individuals are at increased risk for embryonal tumors including Wilms tumor, hepatoblastoma, adrenal neuroblastoma, gonadoblastoma, hepatocellular carcinoma, and medulloblastoma.

Thanatophoric dysplasia (TD) is a short-limb skeletal dysplasia that is usually lethal in the perinatal period. TD is divided into subtypes: TD type 1 is characterized by micromelia with bowed femurs and, uncommonly, the presence of craniosynostosis of varying severity. TD type 2 is characterized by micromelia with straight femurs and uniform presence of moderate-to-severe craniosynostosis with cloverleaf skull deformity. Other features common to type 1 and type 2 include: short ribs, narrow thorax, relative macrocephaly, distinctive facial features, brachydactyly, hypotonia, and redundant skin folds along the limbs. Most affected infants die of respiratory insufficiency shortly after birth. Rare long-term survivors have been reported.

Spondyloepiphyseal dysplasia tarda, Kohn type is characterized by short trunk dwarfism, progressive involvement of the spine and epiphyses and mild-to-moderate intellectual deficit.

Clinical features of SLC26A2-related atelosteogenesis include rhizomelic limb shortening with normal-sized skull, hitchhiker thumbs, small chest, protuberant abdomen, cleft palate, and distinctive facial features (midface retrusion, depressed nasal bridge, epicanthus, micrognathia). Other typical findings are ulnar deviation of the fingers, gap between the first and second toes, and clubfoot. SLC26A2-related atelosteogenesis is usually lethal at birth or shortly thereafter due to pulmonary hypoplasia and tracheobronchomalacia. However, it exists in a continuous phenotypic spectrum with SLC26A2-related diastrophic dysplasia, and long-term survivors have been reported.

The Algerian type of spondylometaphyseal dysplasia (SMDALG) is an autosomal dominant disorder characterized by a short trunk and severe genu valgum. Myopia may be present. The radiologic hallmarks include moderate platyspondyly, particularly with dorsal vertebral flattening, and short ilia with narrow greater sciatic notches. There is generalized metaphyseal dysplasia of the long bones, most conspicuous in the hip and knee and associated with coxa vara and severe genu valgum. The short tubular bones are mildly affected, and epiphyses of the tubular bones are said to be normal (Matsubayashi et al., 2013).

Thanatophoric dysplasia (TD) is a short-limb skeletal dysplasia that is usually lethal in the perinatal period. TD is divided into subtypes: TD type 1 is characterized by micromelia with bowed femurs and, uncommonly, the presence of craniosynostosis of varying severity. TD type 2 is characterized by micromelia with straight femurs and uniform presence of moderate-to-severe craniosynostosis with cloverleaf skull deformity. Other features common to type 1 and type 2 include: short ribs, narrow thorax, relative macrocephaly, distinctive facial features, brachydactyly, hypotonia, and redundant skin folds along the limbs. Most affected infants die of respiratory insufficiency shortly after birth. Rare long-term survivors have been reported.