An unusual presentation of Kabuki syndrome: clinical overlap with CHARGE syndrome

SETting up the genome: KMT2D and KDM6A genomic function in the Kabuki syndrome craniofacial developmental disorder

BACKGROUND

Kabuki syndrome is a congenital developmental disorder that is characterized by distinctive facial gestalt and skeletal abnormalities. Although rare, the disorder shares clinical features with several related craniofacial syndromes that manifest from mutations in chromatin-modifying enzymes. Collectively, these clinical studies underscore the crucial, concerted functions of chromatin factors in shaping developmental genome structure and driving cellular transcriptional states. Kabuki syndrome predominantly results from mutations in KMT2D, a histone H3 lysine 4 methylase, or KDM6A, a histone H3 lysine 27 demethylase.

AIMS

In this review, we summarize the research efforts to model Kabuki syndrome in vivo to understand the cellular and molecular mechanisms that lead to the craniofacial and skeletal pathogenesis that defines the disorder.

DISCUSSION

As several studies have indicated the importance of KMT2D and KDM6A function through catalytic-independent mechanisms, we highlight noncanonical roles for these enzymes as recruitment centers for alternative chromatin and transcriptional machinery.

Clinical and molecular analysis of Guangxi patients with Kabuki syndrome and KMT2D mutations

Kabuki syndrome (KS) is a multiple congenital anomaly syndrome that is characterized by postnatal growth deficiency, hypotonia, short stature, mild-to-moderate intellectual disability, skeletal abnormalities, persistence of fetal fingertip pads, and distinct facial appearance. It is mainly caused by pathogenic/likely pathogenic variants in the KMT2D or KDM6A genes. Here, we described the clinical features of nine sporadic KS patients with considerable phenotypic heterogeneity. In addition to intellectual disability and short stature, our patients presented with a high prevalence of motor retardation and recurrent otitis media. We recommended that KS should be strongly considered in patients with motor delay, short stature, intellectual disability, language disorder and facial deformities. Nine KMT2D variants, four of which were novel, were identified by whole-exome sequencing. The variants included five nonsense variants, two frameshift variants, one missense variant, and one non-canonical splice site variant. In addition, we reviewed the mutation types of the pathogenic KMT2D variants in the ClinVar database. We also indicated that effective mRNA analysis, using biological materials from patients, is helpful in classifying the pathogenicity of atypical splice site variants. Pedigree segregation analysis may also provide valuable information for pathogenicity classification of novel missense variants. These findings extended the mutation spectrum of KMT2D and provided new insights into the understanding of genotype-phenotype correlations, which are helpful for accurate genetic counseling and treatment optimization.

CHARGE syndrome presenting with persistent hypoglycemia: case report and overview of the main genetic syndromes associated with neonatal hypoglycemia

Background

CHARGE syndrome (CS) is an autosomal dominant genetic condition whose recognition in the neonatal period is complicated by considerable phenotypic variability. Pediatric patients with genetic disorders have a known high incidence of hypoglycemia, due to many concurring factors. To date, neonatal hypoglycemia is a feature poorly explored in the literature associated with CS. This paper adds to the existing literature on hypoglycemia in CS and provides a brief review of the mechanisms through which CS, as well as the main genetic syndromes associated with neonatal hypoglycemia, may determine it.

Case presentation

The patient was a term newborn, first-born daughter to non-consanguineous parents. At birth, axial hypotonia with slight hypertonia of the limbs, and dysplastic auricles were noted. The incidental finding of asymptomatic hypoglycemia led to the initiation of glucose infusion on the II day of life, continued for a total of 8 days (maximum infusion rate: 8 mg/kg/min). In-depth endocrinological examinations showed poor cortisol response to the hypoglycemic stimulus, with normal GH values, thyroid function and ACTH. In view of the suspected hypoadrenalism, oral hydrocortisone therapy was initiated. Inappropriately low values of plasmatic and urinary ketones supported the hypothesis of concomitant transient hyperinsulinism, not requiring therapy. A brain MRI was performed, documenting thinning of the optic nerves, non-displayable olfactory bulbs and dysmorphic corpus callosum. An eye examination revealed bilateral chorioretinal coloboma. Temporal bone CT scan showed absence of the semicircular canals. The unexpected findings of coloboma and absence of semicircular canals led to the suspicion of CS, later confirmed by the molecular analysis of CHD7.

Conclusions

It seems important to consider CS in the differential diagnosis of persistent hypoglycemia in newborns with specific anomalies. At the same time, it is advisable to consider the risk of hypoglycemia in children with CS, as well as other genetic syndromes. Awareness of the many possible causes of hypoglycemia in newborns with genetic conditions may help steer the investigations, allowing for an appropriate and timely treatment.

Neuroimaging in Kabuki syndrome and another KMT2D-related disorder

Recognition of distinct phenotypic features is an important component of genetic diagnosis. Although CHARGE syndrome, Kabuki syndrome, and a recently delineated KMT2D Ex 38/39 allelic disorder exhibit significant overlap, differences on neuroimaging may help distinguish these conditions and guide genetic testing and variant interpretation. We present an infant clinically diagnosed with CHARGE syndrome but subsequently found to have a de novo missense variant in exon 38 of KMT2D, the gene implicated in both Kabuki syndrome and a distinct KMT2D allelic disorder. We compare her brain and inner ear morphology to a retrospective cohort of 21 patients with classic Kabuki syndrome and to typical CHARGE syndrome findings described in the literature. Thirteen of the 21 Kabuki syndrome patients had temporal bone imaging (5/13 CT, 12/13 MRI) and/or brain MRI (12/13) which revealed findings distinct from both CHARGE syndrome and the KMT2D allelic disorder. Our findings further elucidate the spectrum of inner ear dysmorphology distinguishing Kabuki syndrome and the KMT2D allelic disorder from CHARGE syndrome, suggesting that these three disorders may be differentiated at least in part by their inner ear anomalies.

Kabuki Syndrome-Clinical Review with Molecular Aspects

Kabuki syndrome (KS) is a rare developmental disorder principally comprised of developmental delay, hypotonia and a clearly defined dysmorphism: elongation of the structures surrounding the eyes, a shortened and depressed nose, thinning of the upper lip and thickening of the lower lip, large and prominent ears, hypertrichosis and scoliosis. Other characteristics include poor physical growth, cardiac, gastrointestinal and renal anomalies as well as variable behavioral issues, including autistic features. De novo or inherited pathogenic/likely pathogenic variants in the KMT2D gene are the most common cause of KS and account for up to 75% of patients. Variants in KDM6A cause up to 5% of cases (X-linked dominant inheritance), while the etiology of about 20% of cases remains unknown. Current KS diagnostic criteria include hypotonia during infancy, developmental delay and/or intellectual disability, typical dysmorphism and confirmed pathogenic/likely pathogenic variant in KMT2D or KDM6A. Care for KS patients includes the control of physical and psychomotor development during childhood, rehabilitation and multi-specialist care. This paper reviews the current clinical knowledge, provides molecular and scientific links and sheds light on the treatment of Kabuki syndrome individuals.

Using Xenopus to analyze neurocristopathies like Kabuki syndrome

Neurocristopathies are human congenital syndromes that arise from defects in neural crest (NC) development and are typically associated with malformations of the craniofacial skeleton. Genetic analyses have been very successful in identifying pathogenic mutations, however, model organisms are required to characterize how these mutations affect embryonic development thereby leading to complex clinical conditions. The African clawed frog Xenopus laevis provides a broad range of in vivo and in vitro tools allowing for a detailed characterization of NC development. Due to the conserved nature of craniofacial morphogenesis in vertebrates, Xenopus is an efficient and versatile system to dissect the morphological and cellular phenotypes as well as the signaling events leading to NC defects. Here, we review a set of techniques and resources how Xenopus can be used as a disease model to investigate the pathogenesis of Kabuki syndrome and neurocristopathies in a wider sense.

De novo loss-of-function variants in X-linked MED12 are associated with Hardikar syndrome in females

PURPOSE

Hardikar syndrome (MIM 612726) is a rare multiple congenital anomaly syndrome characterized by facial clefting, pigmentary retinopathy, biliary anomalies, and intestinal malrotation, but with preserved cognition. Only four patients have been reported previously, and none had a molecular diagnosis. Our objective was to identify the genetic basis of Hardikar syndrome (HS) and expand the phenotypic spectrum of this disorder.

METHODS

We performed exome sequencing on two previously reported and five unpublished female patients with a clinical diagnosis of HS. X-chromosome inactivation (XCI) studies were also performed.

RESULTS

We report clinical features of HS with previously undescribed phenotypes, including a fatal unprovoked intracranial hemorrhage at age 21. We additionally report the discovery of de novo pathogenic nonsense and frameshift variants in MED12 in these seven individuals and evidence of extremely skewed XCI in all patients with informative testing.

CONCLUSION

Pathogenic missense variants in the X-chromosome gene MED12 have previously been associated with Opitz-Kaveggia syndrome, Lujan syndrome, Ohdo syndrome, and nonsyndromic intellectual disability, primarily in males. We propose a fifth, female-specific phenotype for MED12, and suggest that nonsense and frameshift loss-of-function MED12 variants in females cause HS. This expands the MED12-associated phenotype in females beyond intellectual disability.

The KMT2D Kabuki syndrome histone methylase controls neural crest cell differentiation and facial morphology

Kabuki syndrome (KS) is a congenital craniofacial disorder resulting from mutations in the KMT2D histone methylase (KS1) or the UTX histone demethylase (KS2). With small cohorts of KS2 patients, it is not clear whether differences exist in clinical manifestations relative to KS1. We mutated KMT2D in neural crest cells (NCCs) to study cellular and molecular functions in craniofacial development with respect to UTX. Similar to UTX, KMT2D NCC knockout mice demonstrate hypoplasia with reductions in frontonasal bone lengths. We have traced the onset of KMT2D and UTX mutant NCC frontal dysfunction to a stage of altered osteochondral progenitor differentiation. KMT2D NCC loss-of-function does exhibit unique phenotypes distinct from UTX mutation, including fully penetrant cleft palate, mandible hypoplasia and deficits in cranial base ossification. KMT2D mutant NCCs lead to defective secondary palatal shelf elevation with reduced expression of extracellular matrix components. KMT2D mutant chondrocytes in the cranial base fail to properly differentiate, leading to defective endochondral ossification. We conclude that KMT2D is required for appropriate cranial NCC differentiation and KMT2D-specific phenotypes may underlie differences between Kabuki syndrome subtypes.

Phenotypic expansion of KMT2D-related disorder: Beyond Kabuki syndrome

Pathogenic variants in KMT2D, which encodes lysine specific methyltransferase 2D, cause autosomal dominant Kabuki syndrome, associated with distinctive dysmorphic features including arched eyebrows, long palpebral fissures with eversion of the lower lid, large protuberant ears, and fetal finger pads. Most disease-causing variants identified to date are putative loss-of-function alleles, although 15-20% of cases are attributed to missense variants. We describe here four patients (including one previously published patient) with de novo KMT2D missense variants and with shared but unusual clinical findings not typically seen in Kabuki syndrome, including athelia (absent nipples), choanal atresia, hypoparathyroidism, delayed or absent pubertal development, and extreme short stature. These individuals also lack the typical dysmorphic facial features found in Kabuki syndrome. Two of the four patients had severe interstitial lung disease. All of these variants cluster within a 40-amino-acid region of the protein that is located just N-terminal of an annotated coiled coil domain. These findings significantly expand the phenotypic spectrum of features associated with variants in KMT2D beyond those seen in Kabuki syndrome and suggest a possible new underlying disease mechanism for these patients.

The histone methyltransferase KMT2D, mutated in Kabuki syndrome patients, is required for neural crest cell formation and migration

Kabuki syndrome is an autosomal dominant developmental disorder with high similarities to CHARGE syndrome. It is characterized by a typical facial gestalt in combination with short stature, intellectual disability, skeletal findings and additional features like cardiac and urogenital malformations, cleft palate, hearing loss and ophthalmological anomalies. The major cause of Kabuki syndrome are mutations in KMT2D, a gene encoding a histone H3 lysine 4 (H3K4) methyltransferase belonging to the group of chromatin modifiers. Here we provide evidence that Kabuki syndrome is a neurocrestopathy, by showing that Kmt2d loss-of-function inhibits specific steps of neural crest (NC) development. Using the Xenopus model system, we find that Kmt2d loss-of-function recapitulates major features of Kabuki syndrome including severe craniofacial malformations. A detailed marker analysis revealed defects in NC formation as well as migration. Transplantation experiments confirm that Kmt2d function is required in NC cells. Furthermore, analyzing in vivo and in vitro NC migration behavior demonstrates that Kmt2d is necessary for cell dispersion but not protrusion formation of migrating NC cells. Importantly, Kmt2d knockdown correlates with a decrease in H3K4 monomethylation and H3K27 acetylation supporting a role of Kmt2d in the transcriptional activation of target genes. Consistently, using a candidate approach, we find that Kmt2d loss-of-function inhibits Xenopus Sema3F expression, and overexpression of Sema3F can partially rescue Kmt2d loss-of-function defects. Taken together, our data reveal novel functions of Kmt2d in multiple steps of NC development and support the hypothesis that major features of Kabuki syndrome are caused by defects in NC development.

An analysis of body proportions in children with CHARGE syndrome using photogrammetric anthropometry

Background

Growth retardation is one of the main hallmarks of CHARGE syndrome (CS), yet little is known about the body proportions of these children. Knowledge of body proportions in CS may contribute to a better characterization of this syndrome. This knowledge is important when considering starting growth‐stimulating therapy.

Methods

For this cross‐sectional study, we selected 32 children with CS and a CHD7 mutation at the Dutch CHARGE Family Day in 2016 or 2017 and the International CHARGE conference in Orlando, Florida, in 2017. We used photogrammetric anthropometry—a measurement method based on digital photographs—to determine various body proportions. We compared these to measurements in 21 normally proportioned children with growth hormone deficiency, using independent‐samples t test, Mann–Whitney U test, or chi‐square test as appropriate.

Results

Children with CS appear to have a shorter trunk in proportion to their height, head length, and arm length. Children with CS also had smaller feet proportional to tibia length compared to controls. The change of body proportions with age was similar in children with CS and controls.

Conclusion

Body proportions in children with CS are significantly different from those of normally proportioned controls, but a similar change of body proportions with age was noted for both groups.

Genetic analysis of CHARGE syndrome identifies overlapping molecular biology

PURPOSE

CHARGE syndrome is an autosomal-dominant, multiple congenital anomaly condition characterized by vision and hearing loss, congenital heart disease, and malformations of craniofacial and other structures. Pathogenic variants in CHD7, encoding adenosine triphosphate-dependent chromodomain helicase DNA binding protein 7, are present in the majority of affected individuals. However, no causal variant can be found in 5-30% (depending on the cohort) of individuals with a clinical diagnosis of CHARGE syndrome.

METHODS

We performed whole-exome sequencing (WES) on 28 families from which at least one individual presented with features highly suggestive of CHARGE syndrome.

RESULTS

Pathogenic variants in CHD7 were present in 15 of 28 individuals (53.6%), whereas 4 (14.3%) individuals had pathogenic variants in other genes (RERE, KMT2D, EP300, or PUF60). A variant of uncertain clinical significance in KDM6A was identified in one (3.5%) individual. The remaining eight (28.6%) individuals were not found to have pathogenic variants by WES.

CONCLUSION

These results demonstrate that the phenotypic features of CHARGE syndrome overlap with multiple other rare single-gene syndromes. Additionally, they implicate a shared molecular pathology that disrupts epigenetic regulation of multiple-organ development.

Identification of novel KMT2D mutations in two Chinese children with Kabuki syndrome: a case report and systematic literature review

Background

Kabuki syndrome (KS) is a rare pediatric congenital disorder with multiple congenital anomalies and intellectual disabilities, which is inherited in an autosomal dominant manner. Mutations in KMT2D and KDM6A have been proven to be the primary cause in most cases of KS.

Case presentation

Here we report two Chinese boys with clinical features of KS referred to our hospital for clinical diagnosis. Next-generation sequencing was performed on MiSeq to analyze the genetic mutations in both patients. In both, two novel de novo mutations in KMT2D gene (c.5235delA, p.(A1746Lfs*39) and c.7048G > A, p.(Q2350*)) were detected, both of which were subsequently confirmed by the two-generation pedigree analysis based on Sanger sequencing. A systematic literature review of previously reported mutational spectrum of KMT2D was also conducted.

Conclusions

Two novel de novo mutations in KMT2D gene were identified and considered to be pathogenic in both of KS patients. Our data adds information to the growing knowledge on the mutational spectrum of KS.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0545-5) contains supplementary material, which is available to authorized users.

Individual Clinically Diagnosed with CHARGE Syndrome but with a Mutation in KMT2D, a Gene Associated with Kabuki Syndrome: A Case Report

We report a Japanese female patient presenting with classic features of CHARGE syndrome, including choanal atresia, growth and development retardation, ear malformations, genital anomalies, multiple endocrine deficiency, and unilateral facial nerve palsy. She was clinically diagnosed with typical CHARGE syndrome, but genetic analysis using the TruSight One Sequence Panel revealed a germline heterozygous mutation in KMT2D with no pathogenic CHD7 alterations associated with CHARGE syndrome. Kabuki syndrome is a rare multisystem disorder characterized by five cardinal manifestations including typical facial features, skeletal anomalies, dermatoglyphic abnormalities, mild to moderate intellectual disability, and postnatal growth deficiency. Germline mutations in KMT2D underlie the molecular pathogenesis of 52–76% of patients with Kabuki syndrome. This is an instructive case that clearly represents a phenotypic overlap between Kabuki syndrome and CHARGE syndrome. It suggests the importance of considering the possibility of a diagnosis of Kabuki syndrome even if patients present with typical symptoms and meet diagnostic criteria of CHARGE syndrome. The case also emphasizes the impact of non-biased exhaustive genetic analysis by next-generation sequencing in the genetic diagnosis of rare congenital disorders with atypical manifestations.

Clinical and molecular effects of CHD7 in the heart

Heart defects caused by loss-of-function mutations in CHD7 are a frequent cause of morbidity and mortality in CHARGE syndrome. Here we review the clinical and molecular aspects of CHD7 that are related to the cardiovascular manifestations of the syndrome. The types of heart defects found in patients with CHD7 mutations are variable, with an overrepresentation of atrioventricular septal defect and outflow tract defect including aortic arch anomalies compared to nonsyndromic heart defects. Chd7 haploinsufficiency in mouse is a good model for studying the heart effects seen in CHARGE syndrome, and mouse models reveal a role for Chd7 in multiple lineages during heart development. Formation of the great vessels requires Chd7 expression in the pharyngeal surface ectoderm, and this expression likely has an non-autonomous effect on neural crest cells. In the cardiogenic mesoderm, Chd7 is required for atrioventricular cushion development and septation of the outflow tract. Emerging knowledge about the function of CHD7 in the heart indicates that it may act in concert with transcription factors such as TBX1 and SMADs to regulate genes such as p53 and the cardiac transcription factor NKX2.5.

UTX-guided neural crest function underlies craniofacial features of Kabuki syndrome

Kabuki syndrome, a congenital craniofacial disorder, manifests from mutations in an X-linked histone H3 lysine 27 demethylase (UTX/KDM6A) or a H3 lysine 4 methylase (KMT2D). However, the cellular and molecular etiology of histone-modifying enzymes in craniofacial disorders is unknown. We now establish Kabuki syndrome as a neurocristopathy, whereby the majority of clinical features are modeled in mice carrying neural crest (NC) deletion of UTX, including craniofacial dysmorphism, cardiac defects, and postnatal growth retardation. Female UTX NC knockout (FKO) demonstrates enhanced phenotypic severity over males (MKOs), due to partial redundancy with UTY, a Y-chromosome demethylase-dead homolog. Thus, NC cells may require demethylase-independent UTX activity. Consistently, Kabuki causative point mutations upstream of the JmjC domain do not disrupt UTX demethylation. We have isolated primary NC cells at a phenocritical postmigratory timepoint in both FKO and MKO mice, and genome-wide expression and histone profiling have revealed UTX molecular function in establishing appropriate chromatin structure to regulate crucial NC stem-cell signaling pathways. However, the majority of UTX regulated genes do not experience aberrations in H3K27me3 or H3K4me3, implicating alternative roles for UTX in transcriptional control. These findings are substantiated through demethylase-dead knockin mutation of UTX, which supports appropriate facial development.

CHARGE and Kabuki Syndromes: Gene-Specific DNA Methylation Signatures Identify Epigenetic Mechanisms Linking These Clinically Overlapping Conditions

Epigenetic dysregulation has emerged as a recurring mechanism in the etiology of neurodevelopmental disorders. Two such disorders, CHARGE and Kabuki syndromes, result from loss of function mutations in chromodomain helicase DNA-binding protein 7 (CHD7^LOF) and lysine (K) methyltransferase 2D (KMT2D^LOF), respectively. Although these two syndromes are clinically distinct, there is significant phenotypic overlap. We therefore expected that epigenetically driven developmental pathways regulated by CHD7 and KMT2D would overlap and that DNA methylation (DNAm) alterations downstream of the mutations in these genes would identify common target genes, elucidating a mechanistic link between these two conditions, as well as specific target genes for each disorder. Genome-wide DNAm profiles in individuals with CHARGE and Kabuki syndromes with CHD7^LOF or KMT2D^LOF identified distinct sets of DNAm differences in each of the disorders, which were used to generate two unique, highly specific and sensitive DNAm signatures. These DNAm signatures were able to differentiate pathogenic mutations in these two genes from controls and from each other. Analysis of the DNAm targets in each gene-specific signature identified both common gene targets, including homeobox A5 (HOXA5), which could account for some of the clinical overlap in CHARGE and Kabuki syndromes, as well as distinct gene targets. Our findings demonstrate how characterization of the epigenome can contribute to our understanding of disease pathophysiology for epigenetic disorders, paving the way for explorations of novel therapeutics.

KMT2D p.Gln3575His segregating in a family with autosomal dominant choanal atresia strengthens the Kabuki/CHARGE connection

Choanal atresia is rarely reported in Kabuki syndrome, but is a common feature of CHARGE syndrome. Otherwise, the two conditions have a number of overlapping features, and the molecular links between them have recently been elucidated. Here, we report a case of a mother and her two children who presented with congenital choanal atresia. We performed whole exome sequencing on DNA from the mother and her two unaffected parents, and identified a de novo, novel variant in KMT2D. KMT2D p.Gln3575His segregated with disease status in the family, and is associated with a unique and conserved phenotype in the affected family members, with features overlapping with Kabuki and CHARGE syndromes. Our findings further support the potential etiological link between these two classically distinct conditions. © 2016 Wiley Periodicals, Inc.

A novel KMT2D mutation resulting in Kabuki syndrome: A case report

Kabuki syndrome (KS) is a rare genetic syndrome characterized by multiple congenital anomalies and varying degrees of mental retardation. Patients with KS often present with facial, skeletal, visceral and dermatoglyphic abnormalities, cardiac anomalies and immunological defects. Mutation of the lysine methyltransferase 2D (KMT2D) gene (formerly known as MLL2) is the primary cause of KS. The present study reported the case of a 4-year-old Chinese girl who presented with atypical KS, including atypical facial features, unclear speech and suspected mental retardation. A diagnosis of KS was confirmed by genetic testing, which revealed a nonsense mutation in exon 16 of KMT2D (c.4485C>A, Tyr1495Ter). To the best of our knowledge, this is a novel mutation that has not been reported previously. The present case underscores the importance of genetic testing in KS diagnosis.

Kabuki syndrome: expanding the phenotype to include microphthalmia and anophthalmia

Kabuki syndrome is a rare genetic malformation syndrome that is characterized by distinct facies, structural defects and intellectual disability. Kabuki syndrome may be caused by mutations in one of two histone methyltransferase genes: KMT2D and KDM6A. We describe a male child of nonconsanguineous Irish parents presenting with multiple malformations, including bilateral extreme microphthalmia; cleft palate; congenital diaphragmatic hernia; duplex kidney; as well as facial features of Kabuki syndrome, including interrupted eyebrows and lower lid ectropion. A de-novo germline mutation in KMT2D was identified. Whole-exome sequencing failed to reveal mutations in any of the known microphthalmia/anopthalmia genes. We also identified four other patients with Kabuki syndrome and microphthalmia. We postulate that Kabuki syndrome may produce this type of ocular phenotype as a result of extensive interaction between KMT2D, WAR complex proteins and PAXIP1. Children presenting with microphthalmia/anophthalmia should be examined closely for other signs of Kabuki syndrome, especially at an age where the facial gestalt might be less readily appreciable.

Rare ocular features in a case of Kabuki syndrome (Niikawa-Kuroki syndrome)

BACKGROUND

Kabuki syndrome is a multi-system disorder with peculiar facial features, and ophthalmic abnormalities are frequently involved. This case report of a child with Kabuki syndrome describes two new previously unreported ophthalmic conditions.

CASE PRESENTATION

A 3-year-old Taiwanese boy with Kabuki syndrome had a short stature, spinal dysraphism, intellectual disability and typical facial features. Ophthalmic findings which have been previously reported in the literature and in this patient, included ptosis, esotropia, coloboma of the iris, retina, choroid and optic disc, and microcornea. The newly identified ophthalmic features in this patient included colobomatous microphthalmos and a dysplastic and elevated disc without central cupping. The genetic analysis identified an MLL2 gene mutation.

CONCLUSION

The presentations of a dysplastic disc and colobomatous microphthalmia are rarely reported in patients with Kabuki syndrome, but these ophthalmic abnormalities may affect vision. Detailed ophthalmic evaluations in children with Kabuki syndrome are advised.