Coffin-Siris syndrome

The Coffin-Siris Syndrome describes a combination of hypoplastic phalanges with nail hypoplasia, short stature and mental retardation. The syndrome affects more female than male patients.

Those affected have characteristic facial features, such as full lips, a broad mouth, a broad bridge and tip of the nose, as well as long eyelashes and eyebrows. Also typical is a hypertrichosis of the body with sparse head hair.

A majority of patients have a failure to thrive in infancy and early childhood. About half develop seizures, deafness, frequent airway infections, strabismus and ptosis. A third suffers from heart defects, urinary tract disorders and renal malformations. 

The cause of the syndrome are heterozygous mutations in six different genes (ARID1A, ARID1B, SMARCA4, SMARCB1, SMARCE1, SOX11). Although the disease is inherited autosomal dominant, a new mutation is usually present in the patients' genome.