Ībout 30% of cases have no identifiable causative mutation. However, several cases of inherited mutations causing Type 1 or Type 2 Kabuki syndrome are now known. Most cases of Kabuki syndrome occur de novo, that is, the parents are unaffected and the gene was mutated early in embryological development. Type 2 Kabuki syndrome demonstrates an X-linked dominant pattern of inheritance. Approximately 5% of cases of Kabuki syndrome are of Type 2. Type 2 Kabuki syndrome is caused by germline hemizygous (in males) or heterozygous (in females) chromosome deletions or loss of function point variants involving KDM6A, located on the X chromosome. Type 1 Kabuki syndrome demonstrates an autosomal dominant pattern of inheritance. It is estimated that between 55 and 80% of cases of Kabuki syndrome are of Type 1. Type 1 Kabuki syndrome is caused by germline heterozygous loss of function variants in KMT2D (formerly known as the MLL2), located on human chromosome 12. Endocrine abnormalities and immune system abnormalities such as ITP (idiopathic thrombocytopenia) and CVID (common variable immune deficiency) are medical issues that tend to present in older children, adolescents and adults. Older children and adults report difficulties with anxiety. In addition, intellectual impairment, difficulty with visuospatial tasks and maintaining attention usually require an IEP (individualized education plan) if the child attends public school. School age children tend to have fewer medical issues requiring hospitalization, though frequent infections, hearing loss and feeding issues occur. Young children with Kabuki syndrome benefit from early intervention services. Infants and young children often experience difficulties relating to hypotonia, feeding issues/failure to thrive, infections, surgical repair of heart and palate defects and developmental delays. Mild to moderate intellectual disability and mild to severe developmental delay are often associated with Kabuki syndrome. Other common symptoms are skeletal abnormalities, short stature, heart defects, feeding difficulties and a failure to thrive, vision and hearing difficulties, weak muscle tone (hypotonia), small head size ( microcephaly), and frequent infections. Overlapping phenotypic features for patients between KDM6A and KDM6B variations include prominent ears, abnormal dentition, congenital heart disease, feeding difficulties, cryptorchidism, joint hypermobility, developmental delay, hypotonia, and behavioral difficulties. Most people with Kabuki syndrome have distinctive facial features that include arched eyebrows, long eyelashes, elongated eyelids with lower lids that turn out, prominent ears, a flat tip of the nose and a downward slant to the mouth. Specific symptoms for Kabuki syndrome vary, with large differences between affected individuals. Signs and symptoms Ĭhild displaying typical facial phenotype of Kabuki syndrome It is named Kabuki syndrome because of the facial resemblance of affected individuals to stage makeup used in kabuki, a Japanese traditional theatrical form. It was first identified and described in 1981 by two Japanese groups, led by scientists Norio Niikawa and Yoshikazu Kuroki. It is quite rare, affecting roughly one in 32,000 births. It affects multiple parts of the body, with varying symptoms and severity, although the most common is the characteristic facial appearance. Kabuki syndrome (also previously known as Kabuki-makeup syndrome (KMS) or Niikawa–Kuroki syndrome) is a congenital disorder of genetic origin. Loss-of-function mutations in KMT2D or KDM6A genes Type 1 (KMT2D), type 2 (KDM6A) other rare mutations unrecognized for now short 5th finger), cleft palate, dental issues, precocious puberty, scoliosis, hip dysplasia butterfly vertebrae), sparse lateral eyelash, finger anomaly (e.g. coarctation of the aorta), vertebral anamolies (e.g. hypogammaglobinemia), feeding difficulty (infants), obesity (adulthood), short stature, poor sleep, hyperinsulinemia (hypoglycemia), epilepsy, cardiac defects (e.g. anal atresia or intestinal malformation), hearing loss, immune deficiencies (e.g. hypospadias or horseshoe kidney), gi anomalies (e.g. Vary widely among patients but may include: Long eyelashes, depressed nasal tip, atypical fingerprints, ear deformity (macrotia or microtia), hypotonia, joint hyperflexibility, ptosis, blue sclera, cafe au lait spot, GU anomalies (e.g. A child with kabuki syndrome displaying the “scrunchy face”
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