Patient are characterized by: hypertelorism, a wide nasal bridge, a split nasal tip, a broad columella (strip of skin running from the tip of the nose to the upper lip), widely separated narrow nostrils, a long philtrum (vertical groove on the upper lip) and two-sided nasal swellings.Frontorhiny is one of the two subtypes of FND where a genetic mutation has been determined. The mutation has an autosomal recessive inheritance pattern. The syndrome is often seen in siblings and, most of the time, parents are carriers. See Genetics. Craniofrontonasal dysplasia
Craniofrontonasal dysplasia (CFND) is a rare type of FND with X linked inheritance. Multiple features are characteristic for CFND such as craniosynostosis of the coronal sutures (prematurely closed cranial sutures), dry frizzy curled hair, splitting of the nails and facial asymmetry.There is a large variety in phenotype. Women present with a more severe phenotype than men. Females characteristically have FND, craniosynostosis and additional small malformations. Males are usually more mildly affected, presenting with only hypertelorism. The gene that causes CFND is called EFNB1 and is located on the X chromosome. A hypothesis for the more severe outcome in females is based on X-inactivation, which leads to mosaicism. As a result, patients have less functional cells, generating abnormal tissue boundaries, termed "cellular interference". This process almost never occurs in males, as they have less mutagenic material in their genes. EFBN1 also has an important function in males. As the syndrome has an X-linked inheritance pattern, there is no man-to-man inheritance.
These skin lipomas are benign, and are therefore more a cosmetic problem than a functional problem. The skin lipomas can develop on different parts of the face. The most common place is the nose. Other common places are the forehead, the conjunctivae and the frenulum linguae. The amount of skin lipomas is not related to the severity of the midline clefting.Patients with the Pai syndrome have a normal neuropsychological development. Until today there is no known cause for the Pai syndrome. The large variety in phenotypes make the Pai syndrome difficult to diagnose. Thus the incidence of Pai syndrome seems to be underestimated. Acromelic frontonasal dysplasia (AFND)
Acromelic frontonasal dysplasia is a rare subtype of FND. It has an autosomal dominant inheritance. Acromelic frontonasal dysplasia is associated with central nervous system malformations and limb defects including a clubfoot, an underdeveloped shin-bone, and preaxial polydactyly of the feet. Preaxial polydactyly is a condition in which there are too many toes on the side of the big toe. The phenotype of AFND is severe: a type Ia DeMyer and a Sedano type D. In contrast to the other subtypes of FND, AFND has a relatively high frequency of underlying malformations of the brain. Frontorhiny
Frontorhiny is another subtype of FND. It consists of multiple characteristics.