This is a multifaceted hereditary syndrome involving organ systems throughout the body. The facial features superficially resemble those of the cosmetics worn by actors of a Japanese theatrical form known as Kabuki and hence the name.
The type described in this entry is caused by a mutation on the X-chromosome. See Kabuki Syndrome 1 for another more common type that is inherited as an autosomal recessive trait.
The eyebrows are highly arched and broad but the hair may be sparse. The space between the lids is long but not widened. Sometimes the outside portion of the lower eyelid is turned outward to some degree and the upper lids may appear to droop. The eyelashes are thick. Sometimes the eyes are not aligned properly (strabismus). The ears are large and unusually cupped.
Physical growth is slower than normal after birth and many individuals are short in stature. The roof of the mouth is usually highly arched and sometimes has a defect cleft palate). The teeth are small, widely spaced, and frequently malformed. Feeding difficulties are common. Muscles may be ‘floppy’ and joints are often abnormally mobile. Cognitive defects are a feature in most individuals. About half of patients have hearing loss which in at least some cases may be secondary to repeated middle ear infections. Various kidney and liver problems can occur. Cardiac defects are common.
Many instances of Kabuki syndrome occur in the absence of a family history of the syndrome. In the X-linked type described here the mutation is located on the X-chromosome and the syndrome can be seen in both sexes. In females, however, the clinical symptoms are milder than those seen in males.
A male with Kabuki syndrome 2 will not have male offspring with the same syndrome but all his daughters will inherit his mutation and may have clinical features. A mother with the mutation on one of her two X-chromosomes can expect that half her sons and half her daughters will inherit the mutation and have some features of the syndrome.
The typical physical appearance may not be present at birth since the features usually evolve over time. Medical geneticists, neurologists and orthopedists are the most likely to make the diagnosis but because of the extensive and widespread anomalies in most cases the diagnosis is likely the result of a team effort with confirmation by gene testing. Likewise the management team is multidisciplinary with speech and physical therapists, nutritionists, learning specialists, and members of multiple medical specialists involved.