Pai Syndrome is a rare congenital disorder characterized by the triad of a median cleft of the upper lip, intracranial lipoma, and cutaneous polyps. Congenital nasal polyps are the cardinal feature of this condition, with the number of nasal polyps ranging from one to three. These polyps are most commonly found on the nostrils, followed by the columella. Histologically, these polyps have been identified as hamartomas. The median cleft phenotype of this condition shows a wide range of severity, from a midline notch of the upper vermillion to complete cleft extending up to the columella base. In some patients, the cleft is accompanied with duplication of the median maxillary frenulum. Skin lipomas containing cartilage may be seen on the forehead. A number of facial dysmorphpic features have been reported in the patients. However, only two dysmorphic signs, hypertelorism and nasal cleft, seem to significantly associate with the clinical spectrum. Some affected patients also feature hypertelorism with ocular anomalies, including anterior segment dysgenesis, persistent papillary membrane, corneal leukoma, microcornea, posterior lenticonus, heterochromia iris and conjunctival lipoma. Neuropsychological development is usually normal.
Pai Syndrome is extremely rare, with less than 50 patients being reported worldwide with this condition. Diagnosis is made on the basis of the clinical features. Since congenital nasal polyps have so far been seen in all affected patients, it is a key feature in the diagnosis and due to its rare nature is extremely helpful in considering the differential diagnoses. Nasal polyps may result in respiratory impairment, increased respiratory infections, speech impediments or early childhood difficulties in eating solids. Detection of potential oral or respiratory difficulties in newborns must be treated immediately. Multistage craniofacial surgery may be necessary in many cases. Prognosis is generally good.
The etiology of Pai Syndrome is unknown, although some researchers have proposed that a genetic defect in mesodermal differentiation could account for the clinical features. The disease seems to follow an autosomal dominant mode of inheritance, although X-linked or recessive inheritance has also been proposed. A single patient was found to have a de novo reciprocal translocation, 46,X,t(X;16)(q28:q11.2).