What is Coffin-Siris Syndrome?

Pathology1: CSS

Type of pathology: Congenital Malformations, Deformities and Chromosomal Anomalies

Coffin-Siris syndrome (CSS) is a rare congenital multisystemic genetic disorder characterised by aplasia or hypoplasia of the distal phalanx or nail of the little finger, developmental delay, intellectual disability, coarse facial features and other variable clinical manifestations.


To date, more than 100 cases of confirmed CSS have been clinically reported. The exact prevalence and incidence is unknown, but the disease is probably under-diagnosed.

Clinical description

Coffin-Siris syndrome is a clinically and genetically heterogeneous disease involving a wide range of major and minor manifestations. The most representative features are mild to severe cognitive or developmental delay (in all patients), hypoplasia or aplasia of the nail or distal phalanx of the little finger (in almost all patients at birth) and coarse facial features (usually observed over time).

Distinctive facial features include bushy eyebrows and long eyelashes, broad nasal bridge, wide mouth with thick, everted upper and lower lips, and anomalous position or shape of the ears. Common minor features include short stature, growth retardation, feeding difficulties, microcephaly, ophthalmological manifestations (cataracts, eyelid ptosis, strabismus), cardiac anomalies (ventricular septal defects or atrial septal defects, tetralogy of Fallot, patent ductus arteriosus), hypertrichosis (of arms, face or back) and sparse scalp hair.

Other minor features include neurological involvement (Dandy-Walker malformation, simplification of cerebral convolutions, agenesis of the corpus callosum, seizures and hypotonia), hearing loss, joint laxity, genitourinary and renal malformations and frequent infections.

Developmental delay and scoliosis occur in infancy and childhood.