Roberts syndrome is a rare genetic disorder characterized by growth delays before and after birth (pre- and postnatal growth deficiency); malformations of the arms and legs (limbs); distinctive abnormalities of the skull and facial (craniofacial) region. Mental retardation occurs in some cases; normal intelligence has also been reported.
In infants with Roberts syndrome, the arms and legs may be incompletely developed (limb reduction abnormalities), however, such limb defects are usually symmetrical which are distinct from the asymmetrical limb defects in CdLS. Such abnormalities may range from absence of all four limbs (tetraphocomelia) to less severe degrees of limb reduction, such as underdevelopment and/or absence of certain bones of the upper arms (humeri), forearms (radii and/or ulnae), thighs (femurs), shins (tibiae), and/or outside of the lower legs (fibulae). Characteristic craniofacial abnormalities may include an unusually small, broad head (microbrachycephaly); abnormal grooves on either side of the upper lip (bilateral cleft lip); incomplete development of the roof of the mouth (cleft palate); thin, small wings of the nose (hypoplastic nasal alae); and/or low-set, malformed (dysplastic) ears. Additional abnormalities are often present. Robert's syndrome is probably genetically heterogeneous. While it is inherited as an autosomal recessive trait in most families, the possibility of new mutation in an autosomal dominant gene cannot be excluded.
For many years, some researchers believed that Robert's syndrome and SC phocomelia syndrome were separate disorders. However, researchers now believe that the two disorders are different expressions of one distinct disorder.