Coffin-Siris Sydrome is a rare genetic disorder which causes mental retardation and absent fifth finger and toe nails. Synonyms include Dwarfism-Onychodysplasia, Fifth Digit Syndrome, Mental Retardation with Hypoplastic 5th Fingernails and Toenails, and Short Stature-Onychodysplasia.
At birth, infants with Coffin-Siris syndrome will have an absence or incomplete formation of the fifth fingernail and tip of the fifth finger (distal phalanx). This absence may also occur in the toes or in other fingers. Infants may have an abnormal facial appearance at birth. As the child grows, the facial abnormalities characteristic of Coffin-Siris syndrome become more apparent. Sparse scalp hair in an infant usually becomes more dense with age and excessive hair growth (hirsutism) develops. Infants typically have sucking problems and feeding difficulties that may continue with age. There is a delay in both gross and fine motor skills. Developments such as sitting up and walking may be delayed or not possible, depending upon the severity of the disorder. Speech is usually delayed and most children are better able to respond to language rather than express it. Some older children are able to form short sentences and answer simple questions. Mental retardation is usually moderate. Social adaptation is usually delayed.
Autosomal recessive inheritance is the most likely, but sporadic mutations and autosomal dominant cases may also occur.
At present, the diagnosis of Coffin-Siris syndrome is based upon clinical findings. There are no laboratory tests that can confirm the disorder. The combination of symptoms such as coarse facial appearance, fifth finger appearance, and developmental delay would suggest Coffin-Siris syndrome. X ray of the hands to reveal the absence of the fifth finger bone is usually the best indicator of this syndrome. Neonatal ultrasounds for cardiac, kidney (renal), and other malformations that may be present with this disorder can also be informative. Prenatal ultrasound may show intrauterine (occurring within the uterus) growth retardation, and can reveal the condition of the fifth finger. However, these symptoms alone cannot conclusively lead to a prenatal diagnosis of Coffin-Siris syndrome.
Infants born with Coffin-Siris syndrome may experience a delay or absence of motor and mental activities, but with support can live into adulthood. The lifestyle of an individual with Coffin-Siris syndrome is dependent to a large extent upon the degree of mental retardation and developmental delay.
The treatment or therapy required for children with Coffin-Siris syndrome is based on the particular symptoms of each individual. Some children may require surgery to repair malformations that may be seen with this disorder. This ranges from cleft palate repair to cardiac, renal, or other surgery. Speech therapy and special education may be considered depending upon the degree of mental retardation, developmental delay, and motor impairment.