What Is Kabuki Syndrome?
Kabuki syndrome (KS) is a classic disease marked by characteristic facial dysmorphism, growth retardation, and poor psychomotor development. It was first described in the early 1980s in Japan. Since then, the prevalence is estimated at 1 in 32 thousand each year globally.
It occurs due to developmental delay in the affected individuals due to weak muscle tone or altered body structures that affect their appearance. In the affected individuals, some of the typical features are elongation of the structures surrounding their eyes, a shortened and depressed nose, upper lip thinning with a contrast thickening of the lower lip, large prominent ears, hypertrichosis (excessive hair growth), and scoliosis (abnormal spine curvature). Other characteristics include heart, brain, gastrointestinal, and kidney manifestations. Furthermore, these individuals may also face behavioral issues, including signs of autism.
What Is the Etiology and Diagnosis of Kabuki Syndrome?
A spectrum of multi-organ manifestations and genetic etiology make KS a diagnostic challenge. It is because it can be similar to many other developmental diseases or anomalies. However, KS is increasingly being researched and focused upon in family medicine, pediatrics, and even the dental setting for craniofacial (skull) and oral anomalies. These anomalies can help the dentist detect the syndrome and arrive at a diagnosis.
Any feature of facial dysmorphism is enough to raise suspicions of KS. Still, it may not be enough, because only a genetic diagnosis can confirm KS. A genetic diagnosis can be performed using different methods.
A. Next-Generation Sequencing: It determines the order of nucleic acids or targeted regions of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).
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It is also called Sanger sequencing, which was more commonly used in the past.
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It is a popular technique that aims to identify the disease-causing or pathogenic variant or the specific genes for causing KS.
B. Whole-Exome Sequencing: Whole-exome sequencing detects all the protein-coding regions of genes.
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It is an alternative genetic diagnostic technique to confirm the presence of the same pathogenic variants that may cause KS.
How Is a Diagnosis of Kabuki Syndrome Confirmed?
There are some supportive features and characteristics of KS that can be taken as inclusion criteria for confirmation of KS diagnosis. If patients of any age are affected by one of these major criteria, a diagnosis of KS is confirmatory.
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History of infantile hypotonia.
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Developmental delays.
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Detection of a pathogenic or a likely pathogenic variant by genetic diagnostic tests.
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Clinically, patients present typical dysmorphic features such as longer palpebral features, lower eyelid eversions, arched or broad eyebrows with notching, depressed nasal tips, prominent or cupped ears, or persistent fingertip pads.
Other supportive clinical features for confirming KS are the generalized short stature of the individuals affected with a shorter head (microcephaly), cleft palate, lip pits, hearing loss, congenital heart defects, feeding difficulties, and immunological disorders.
What Are the Craniofacial, Jaw, and Oral Anomalies in Kabuki Syndrome?
The esthetics of the individual and their functions are severely compromised because of oral anomalies, craniofacial distortions, and skeletal abnormalities. The systemic status of the suffering individuals is also severely affected due to the involvement of multiorgan systems. Hence, interdisciplinary management must be done by the respective specialists. The various craniofacial, jaw, and oral anomalies in KS are:
A. Craniofacial Features:
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Long or wide palpebral fissures may be present.
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There may be an eversion of lower lateral eyelids.
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Arched eyebrows with scattered hair on the sides.
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While the ears are either large or prominent, the nasal tip is depressed.
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Some have nystagmus (rapid, involuntary eye movements) and strabismus (eyes that do not look in the same direction).
B. Jaw Features: There is a midface hypoplasia (tissue underdevelopment) or an underdeveloped lower jaw (mandible). Hence, there is mandibular hypoplasia in some patients. There are changes in the frontonasal bone length and dysmorphic features such as cleft palate and cranial base ossification (a normal developing process) deficits that are more complex to treat.
C. Oral Anomalies: These are present in about 60 percent of KS cases, which makes the dentist one of the preliminary doctors to detect or report the syndrome. Documented cases show that the suffering KS individuals have typical dental pathologies such as:
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Several congenitally missing teeth.
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Malocclusion or improper bite.
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A high-arched palate.
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An abnormal dentition (teeth arrangement).
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Widely spaced teeth and spacing.
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Hypodontia or a lesser number of teeth.
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Conical-shaped or screwdriver-shaped incisors (also seen in Congenital Syphilis).
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Delayed permanent tooth eruption.
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Ectopic (in an abnormal place) upper molars may be present.
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Lateral upper incisors and lower molar tooth buds may be absent.
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Taurodontism or bull’s teeth.
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Nursing bottle syndrome (which occurs due to children with a milk bottle in their mouth while sleeping) is a common feature associated with screwdriver-shaped incisors or high-arched maxilla.
What Is the Orofacial Management of Kabuki Syndrome?
Proper dental management may be of several steps requiring skilled oral and maxillofacial surgeons to manage the complexity of the condition. Proper dental care, tooth extractions, and fluoride treatments are essential in the patients of KS. Tooth extractions are recommended by the oral surgeon for those with a poor prognosis. Further, fluoride treatment is an effective treatment modality recommended by many dentists for retaining the remaining teeth. Studies suggest that several permanent teeth can be missing in KS patients. Hence, implants and orthodontic treatment are crucial to correct jaw and oral anomalies at a later age.
Conclusion
To conclude, the systemic and oral management of Kabuki syndrome is extremely challenging and complex. However, dentists can aim to diagnose and improve the quality of life in patients affected by KS by timely management. It can be done through orofacial surgical procedures, orthodontic, and fluoride treatment to restore facial esthetics, form, and function.
