Some features of Kabuki syndrome are present at birth (congenital). Other features become apparent as an affected child ages. The specific findings and the severity of those findings can vary from one person to another. A wide variety of findings affecting multiple organ systems of the body can potentially occur. It is important to note that affected individuals may not have all of the features discussed below. Parents of an affected child should talk to their physician and medical team about their child’s specific case, associated features and overall prognosis.
Children with Kabuki syndrome have a distinctive facial appearance, which includes abnormally long openings between the eyelids (palpebral fissures), lower eyelids that are turned outward (everted), prominent eyelashes, arched eyebrows, a broad nose with a flattened or depressed tip, and large, misshaped ears. The distinctive facial appearance associated with Kabuki syndrome develops slowly over several years. Additional facial features include a bluish tinge to the Whites of the eyes (blue sclerae), drooping of the upper eyelid (ptosis), misaligned eyes (strabismus), a highly arched roof of the mouth or a cleft palate, depressions involving the inside of the lower lips (lip pits), and an abnormally Small jaw (micrognathia).
Growth deficiency is common in individuals with Kabuki syndrome usually becoming apparent during the first year of life (postnatal growth deficiency). Growth deficiency can become more noticeable as affected children grow older. Eventually, affected individuals may be notably below average height for their age (Short stature). In rare cases, some children may have had partial growth hormone deficiency.
In addition to growth deficiency, children with Kabuki syndrome may also have mild to moderate intellectual disability. Severe Intellectual disability is extremely rare and some children have no intellectual disability. Some children may have seizures, Diminished muscle tone (hypotonia) and microcephaly, a condition in which the circumference of the head is abnormally small. Seizures can develop right after birth (neonatal period) or as late as 12 years of age. One rare cause of Seizures occurring right after birth is very Low blood sugar due to too much insulin (hyperinsulinism). This requires immediate treatment to avoid damage to the brain. All neonates with a known or suspected diagnosis of Kabuki syndrome should undergo routine blood sugar monitoring for the first few days of life.
Some children with Kabuki syndrome experience speech delays. Palate abnormalities and Hearing loss may contribute to speech delays. Some children with Kabuki syndrome may develop behavioral abnormalities including anxiousness and a tendency to fixate on objects or activities. They may also dislike certain stimuli including certain noises, smells or textures. Some children with Kabuki syndrome appear to be particularly fond of music. A learning environment that stresses audio-verbal learning over visual learning may be helpful.
Children with Kabuki syndrome may also have Feeding difficulties including gastroesphogeal reflux, poor sucking ability, and difficulty absorbing or digesting nutrients from food (malabsorption). Consequently, many affected children may fail to gain weight and grow at the rate expected for children of their age and sex (failure to thrive). However, as children enter adolescents, they have a tendency to gain too much weight, which can make other health problems (such as joint dislocations) worse. Some children may be susceptible to recurring infections including upper Respiratory infections and pneumonia. Many children have recurrent ear infections (otitis media) which may contribute to hearing loss.
Dental abnormalities such as missing, misaligned or misshaped teeth have been reported. Small and/or thin fingernails and toenails are sometimes seen. In addition, some children will have prominences involving the finger tips, known as persistent fetal finger pads.
Skeletal abnormalities may occur in some patients including abnormally Short fingers and toes (brachydactyly), pinkies that are bent (clinodactyly), flat feet, loose (lax) joints, abnormalities of the vertebrae, cranial malformations, and abnormal curvature of the spine (scoliosis or kyphosis). Affected individuals may also be prone to dislocating their hips or kneecaps.
Some children with Kabuki syndrome may have certain heart abnormalities that are present from birth (congenital heart defects). The two most commonly reported Heart defects in children with Kabuki syndrome include narrowing of the main artery of the body (coarctation of the aorta) and holes in the membranes (septa) that separate the chambers of the heart (ventricular or atrial septal defects).
In some patients, additional features involving a variety of organ systems may also be present. Possible kidney (renal) abnormalities include malformation or underdevelopment of the kidneys (renal dysplasia or hypoplasia), obstruction of the normal flow of urine from the kidneys (hydronephrosis) and fusion of the kidneys at the base forming a horseshoe shape (horseshoe kidneys). Gastrointestinal abnormalities include malrotation of the colon and absence or blockage of the anal opening (anal atresia). Immunological deficiencies and/or a higher chance of developing autoimmune disorders have also been reported. Affected females may also experience early onset of breast development (premature thelarche), while some males may have undescended testicles (cryptorchidism).