A rare chromosome X structural anomaly with a highly variable phenotype. Principle characteristics are developmental delay, intellectual disability, short stature, craniofacial dysmorphism (including microcephaly, facial asymmetry, hypertelorism, long palpebral fissures, epicanthus, low-set or malrotated ears, broad nose with a flat nasal bridge, anteverted nares, long philtrum, thin upper lip, high arched palate, micrognathia) and skeletal anomalies (for example cubitus valgus, talipes equinovarus). Patients may also present heart malformations (for example ventricular septal defects, mitral valve stenosis), sacral dimple, soft tissue syndactyly, pigmented naevi and seizures. [from
SNOMEDCT_US]