Kabuki syndrome affects several parts of the body and is evident from the birth of the infant. Along with the characteristic symptoms of this condition, a wide variety of other health ailments can also occur among these cases that include frequent ear infections, hearing loss, heart abnormality and early puberty. The severity of this condition varies among the affected individuals. Although the exact prevalence of this syndrome is not known, it is estimated to affect around 1 in 32,000 to 86,000 individuals.
Causes
This syndrome develops as the result of the mutation in the genes KMT2D or KDM6A. Most of the cases develop from the mutation in the gene KMT2D which produces an enzyme known as lysine-specific methyltransferase 2D functioning as a histone methyltransferase that alters proteins called histones. The lysine-specific methyltransferase 2D are important for the regulation of certain genes that are necessary for the development. The KDM6A gene produces enzymes known as lysine-specific demethylase 6A which also regulates the activity of various genes. The genetic mutation results in the absence of the corresponding functional enzyme which can impair the activation of various genes in several organs and tissues of the body resulting in the features characteristic of this syndrome. The KMT2D gene is inherited in an autosomal dominant manner where one copy of the defective gene can cause this condition and the KDM6A gene is inherited in an X-linked dominant pattern where the genetic mutation is present in one of the sex chromosome. However, several cases of this condition also develop from a new mutation with no family history.
Symptoms
The symptoms of this condition are evident at the birth of the infant. Some of the characteristic facial features include wide eyes, long and thick eyelashes, prominent ears, cleft lip, cleft palate, irregular teeth and a depressed tip of the nose. The affected cases also present mild to moderate intellectual disability with speech and language delay. Additional conditions include congenital heart defects, skeletal abnormalities such as joint dislocations, weak muscle tone (hypotonia), seizures, small head and feeding difficulties.
Diagnosis
The diagnosis of this condition is based on the identification of five features associated with this syndrome such as the skeletal abnormalities, intellectual disability, distinctive facial features and dermatoglyphic abnormalities. Blood tests and chromosomal studies may be required to rule out other possible causes. The genetic testing can confirm the diagnosis by identifying the genes that are responsible for causing this syndrome.
Treatment
There is no specific treatment for this condition. The treatment is focused on various symptoms that are evident in each case. The coordinated efforts of various medical specialists such as pediatricians, surgeons, speech pathologists and cardiologists may be necessary to devise an effective treatment plan. Feeding difficulties may be treated by placing a gastronomy tube. If hormone deficiency is evident, this will be addressed with the supplement growth hormone. Hearing problems requires hearing aids and surgery may be optional for those with cleft palate, cardiac defects and hip dislocation. The affected children may also benefit from special therapies such as physical, special remedial education and speech therapy.
References
https://rarediseases.org/rare-diseases/kabuki-syndrome/
https://ghr.nlm.nih.gov/condition/kabuki-syndrome#inheritance
https://rarediseases.info.nih.gov/diseases/6810/kabuki-syndrome
