Kabuki syndrome and cancer in two patients

Primary CNS Burkitt Lymphoma Presenting as Sudden Bilateral Blindness in a Patient With Underlying Kabuki Syndrome: A Case Report

Burkitt lymphoma is an aggressive B-cell non-Hodgkin lymphoma (NHL). Primary CNS lymphoma (PCNSL) is a rare disease, and the subtype of Burkitt lymphoma presenting as a sole CNS lesion is an even rarer diagnosis. Acute sudden blindness is a rare presenting symptom of PCNSL or NHL in general. We present an interesting case of a four-year-old boy with dysmorphic features whose visual examination showed a sudden bilateral loss of vision. There was bilateral eye proptosis and complete ptosis. Extraocular muscles were fixed straight. The pupils were fixed and mid dilated bilaterally and there was grade 3/4 papilledema in both eyes. Neuroimaging showed a mass in the base of the skull, extending to orbits and sinuses. A cervical biopsy of the enlarged lymph nodes was taken and a histopathological diagnosis of Burkitt lymphoma was made. Genetic analysis showed a GNB1 mutation, and the patient was diagnosed with Kabuki syndrome by a pediatrician, based on characteristic dysmorphic features. Treatment with steroids and chemotherapy was initiated.

Unmasking the challenges of Kabuki syndrome in adulthood: A case series

Kabuki syndrome is a recognizable Mendelian disorder characterized by the clinical constellation of childhood hypotonia, developmental delay or intellectual impairment, and characteristic dysmorphism resulting from monoallelic pathogenic variants in KMT2D or KDM6A. In the medical literature, most reported patients are children, and data is lacking on the natural history of the condition across the lifespan, with little known about adult-specific presentations and symptoms. Here, we report the results of a retrospective chart review of eight adult patients with Kabuki syndrome, seven of whom are molecularly confirmed. We use their trajectories to highlight the diagnostic challenges unique to an adult population, expand on neurodevelopmental/psychiatric phenotypes across the lifespan, and describe adult-onset medical complications, including a potential cancer risk and unusual and striking premature/accelerated aging phenotype.

Molecular characterization of an embryonal rhabdomyosarcoma occurring in a patient with Kabuki syndrome: report and literature review in the light of tumor predisposition syndromes

Kabuki syndrome is a well-recognized syndrome characterized by facial dysmorphism and developmental delay/intellectual disability and in the majority of patients a germline variant in KMT2D is found. As somatic KMT2D variants can be found in 5-10% of tumors a tumor predisposition in Kabuki syndrome is discussed. So far less than 20 patients with Kabuki syndrome and a concomitant malignancy have been published. Here we report on a female patient with Kabuki syndrome and a c.2558_2559delCT germline variant in KMT2D who developed an embryonal rhabdomyosarcoma (ERMS) at 10 years. On tumor tissue we performed DNA-methylation profiling and exome sequencing (ES). Copy number analyses revealed aneuploidies typical for ERMS including (partial) gains of chromosomes 2, 3, 7, 8, 12, 15, and 20 and 3 focal deletions of chromosome 11p. DNA methylation profiling mapped the case to ERMS by a DNA methylation-based sarcoma classifier. Sequencing suggested gain of the wild-type KMT2D allele in the trisomy 12. Including our patient literature review identified 18 patients with Kabuki syndrome and a malignancy. Overall, the landscape of malignancies in patients with Kabuki syndrome was reminiscent of that of the pediatric population in general. Histopathological and molecular data were only infrequently reported and no report included next generation sequencing and/or DNA-methylation profiling. Although we found no strong arguments pointing towards KS as a tumor predisposition syndrome, based on the small numbers any relation cannot be fully excluded. Further planned studies including profiling of additional tumors and long term follow-up of KS-patients into adulthood could provide further insights.

From Genotype to Phenotype-A Review of Kabuki Syndrome

Kabuki syndrome (KS) is a rare neuro-developmental disorder caused by variants in genes of histone modification, including KMT2D and KDM6A. This review assesses our current understanding of KS, which was originally named Niikawa-Kuroki syndrome, and aims to guide surveillance and medical care of affected individuals as well as identify gaps in knowledge and unmet patient needs. Ovid MEDLINE and EMBASE databases were searched from 1981 to 2021 to identify reports related to genotype and systems-based phenotype characterization of KS. A total of 2418 articles were retrieved, and 152 were included in this review, representing a total of 1369 individuals with KS. Genotype, phenotype, and the developmental and behavioral profile of KS are reviewed. There is a continuous clinical phenotype spectrum associated with KS with notable variability between affected individuals and an emerging genotype-phenotype correlation. The observed clinical variability may be attributable to differences in genotypes and/or unknown genetic and epigenetic factors. Clinical management is symptom oriented, fragmented, and lacks established clinical care standards. Additional research should focus on enhancing understanding of the burden of illness, the impact on quality of life, the adult phenotype, life expectancy and development of standard-of-care guidelines.

Neuroblastic tumors and neurofibromatosis type 1: A retrospective multicenter study in Italy and systematic review of the literature

BACKGROUND

Neuroblastic tumors (NBTs) are the most common extra-cranial solid tumors of childhood. Neurofibromatosis type 1 (NF1) is the most common neurocutaneous disorder with a predisposition to tumors. The co-occurrence of NBTs in the setting of NF1 has been occasionally reported, suggesting a non-casual association and likely configuring a spectrum of neural crest-derived disorders.

AIM OF THE STUDY

To explore the occurrence of NBTs within NF1 and to report on its natural history, therapeutic strategies, and outcomes in an Italian cohort of children with NF1 and in the literature.

SUBJECTS AND METHODS

Study (a): a retrospective analysis of questionnaire-based data [years 1979-2017] derived from the databases of the Italian Registry for Neuroblastoma (RINB) of the Italian Society of Pediatric Onco-Haematology (AIEOP); and Study (b): a systematic review search on NF1/NB co-occurrence.

RESULTS

Study (a) identified eight children with NBTs, 0.2% of patients registered in the RINB, fulfilling the diagnostic criteria for NF1. The primary site of NBTs was abdominal in six patients. The NBTs were neuroblastoma (NB) in five patients, ganglioneuroblastoma (GNB) in one, patient, and ganglioneuroma (GN) in two. Metastatic diffusion occurred in three out of eight children. MYCN gene testing, performed in the tumors of five patients, resulted not-amplified. The major features of NF1 included the following: NF1 family history in four patients, café-au-lait spots in all, freckling in six, Lisch nodules in three, and neurofibromas in three. With regard to the outcome, four children survived three of these for the progression of NB and one for a second tumor. Study (b) identified 12 patients with NF1/NB from the years 1966-2017, and the median age at diagnosis was 27 months (range = 0-168 months). The primary site of NB was thoracic. The prevalent histotype was NB in nine patients, GNB in two, and GN in one. Eight/nine NBs were metastatic. The MYCN gene was amplified in the only studied case. The NF1 features included NF1 family history in seven patients; the major NF1 features were café-au-lait spots in nine patients, freckling in one, Lisch nodules in none, and neurofibromas in six. The outcome was good for only two children, while eight children died of neuroblastoma, at a median age of 49.5 months (range = 2.4-174 months), with a median survival time of 21.75 months after diagnosis.

CONCLUSIONS

To our knowledge, this represents the first systematic study on the occurrence of NBTs in NF1. This confirms that NBs are rare per se in the setting of NF1 (0.2% of all NBs) and even if compared to the overall frequency of malignancies in NF1 (i.e., 14.7%). The male:female ratio in study (a) (0.6) was different from what was recorded in study (b) (1.5) and in line with the overall increased frequency of malignancies in females with NF1. The median ages at diagnosis of NB in either study (a) or (b) were concordant with what occurred in the NB population. In study (a) versus study (b), the frequency of metastatic diffusion was lower, likely indicating less awareness on work-ups for malignancies in old NF1 series in the literature. The outcome was much better in study (a) than in study (b), indicating that multidisciplinary treatment for NB is highly recommended.

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.

Cancer-derived UTX TPR mutations G137V and D336G impair interaction with MLL3/4 complexes and affect UTX subcellular localization

The ubiquitously transcribed tetratricopeptide repeat on X chromosome (UTX) is a major histone H3 lysine 27 (H3K27) demethylase and the mixed-lineage leukemia (MLL) proteins are the H3K4 methyltransferases. UTX is one of the major components of MLL3- and MLL4-containing (MlLL3/4) complexes and likely has functions within the complexes. Although UTX is frequently mutated in various types of cancer and is thought to play a crucial role as a tumor suppressor, the importance of UTX interaction with MLL3/4 complexes in cancer formation is poorly understood. Here, we analyzed the ability of cancer-derived UTX mutant proteins to interact with ASH2L, which is a common core component of all the MLL complexes, and MLL3/4-specific components PTIP and PA1, and found that several single-amino acid substitution mutations in the tetratricopeptide repeat (TPR) affect UTX interaction with these components. Interaction-compromised mutants G137V and D336G and a TPR-deleted mutant Δ80-397 were preferentially localized to the cytoplasm, suggesting that UTX is retained in the nucleus by MLL3/4 complexes through their interaction with the TPR. Intriguingly, WT UTX suppressed colony formation in soft agar, whereas G137V failed. This suggests that interaction of UTX with MLL3/4 complex plays a crucial role in their tumor suppressor function. Preferential cytoplasmic localization was also observed for endogenous proteins of G137V and another mutant G137VΔ138 in HCT116 created by CRISPR-Cas9 gene editing. Interestingly, expression levels of these mutants were low and MG312 stabilized both endogenous as well as exogenous G137V proteins. These results reveal a novel mechanism of UTX regulation and reinforce the importance of UTX interaction with MLL3/4 complexes in cancer formation.

Diffuse Adenomatosis and Hepatocellular Carcinoma Treated with Liver Transplantation in an Adolescent Female with Kabuki Syndrome with a Novel KMT2D Gene Mutation

Kabuki syndrome (KS) is a rare disorder primarily associated with mutations in the KMT2D and KDM6A genes. Several tumors have been reported with KS; however, there have been no reports of hepatocellular carcinoma (HCC) or hepatic adenomatosis. We present an adolescent girl with KS and a novel KMT2D mutation who developed diffuse adenomatosis, HCC, and subsequently underwent liver transplantation.

Loss of KDM6A Activates Super-Enhancers to Induce Gender-Specific Squamous-like Pancreatic Cancer and Confers Sensitivity to BET Inhibitors

KDM6A, an X chromosome-encoded histone demethylase and member of the COMPASS-like complex, is frequently mutated in a broad spectrum of malignancies and contributes to oncogenesis with poorly characterized mechanisms. We found that KDM6A loss induced squamous-like, metastatic pancreatic cancer selectively in females through deregulation of the COMPASS-like complex and aberrant activation of super-enhancers regulating ΔNp63, MYC, and RUNX3 oncogenes. This subtype of tumor developed in males had concomitant loss of UTY and KDM6A, suggesting overlapping roles, and points to largely demethylase independent tumor suppressor functions. We also demonstrate that KDM6A-deficient pancreatic cancer is selectively sensitive to BET inhibitors, which reversed squamous differentiation and restrained tumor growth in vivo, highlighting a therapeutic niche for patient tailored therapies.

Hepatoblastoma in an 11-year-old: Case report and a review of the literature

RATIONALE

Hepatoblastoma is a rare malignancy. Approximately 100 cases are diagnosed yearly in the United States. The highest incidence occurs in infants and in children younger than 5 years. Cases involving patients older than 5 years are very rare. We describe the case of a patient who was diagnosed with hepatoblastoma at an atypical age of presentation for this type of malignancy. We also performed Ovid MEDLINE search for hepatoblastoma and epidemiology reports occurring in children between the ages of 5 and 18 years. In this article we review the epidemiology and summarize case reports published between 1997 and 2012 of patients with hepatoblastoma, who were older than 5 years.

PATIENT CONCERNS AND DIAGNOSIS

Our patient is an 11 year old boy with stage IV hepatoblastoma with lung and omental metastases at diagnosis.

INTERVENTIONS

The patient received 7 cycles of chemotherapy following the treatment plan of COG protocol AHEP 0731, off study. He also had tumor resection and omentectomy and achieved complete remission.

OUTCOMES

He later had disease recurrence and after undergoing treatment with different modalities, ultimately died of his disease. Review of SEER program data shows that the incidence of hepatoblastoma in children above the age of 5 years is too infrequent to be calculated. Literature review revealed 13 cases of patients diagnosed at age older than 5 years. Most cases were published due to unusual associations and/or complications. There are no obvious unifying characteristics for these cases, although there may be a slight male preponderance and many patients in this selected series presented with elevated Alpha-fetoprotein.

LESSONS

The reported case is rare, given the very low incidence of hepatoblastoma outside of infancy. A systematic review of characteristics and outcomes for patients older than 5 years who are enrolled in cooperative group hepatoblastoma trials may reveal important information about the epidemiology and tumor biology in this rare patient population.

Spinal ependymoma in a patient with Kabuki syndrome: a case report

BACKGROUND

Kabuki syndrome is a rare disorder characterized by the association of mental retardation and postnatal growth deficiency with distinctive facial appearance, skeletal anomalies, cardiac and renal malformation. Two causative genes have been identified in patients with Kabuki syndrome. Mutation of KMT2D (MLL2) was identified in 55-80% of patients, while 9-14% of KMT2D negative patients have mutation in KDM6A gene. So far, few tumors have been reported in patients with Kabuki syndrome. We describe the first case of a patient with spinal ependymoma and Kabuki syndrome.

CASE PRESENTATION

A 23 years old girl followed at our Center for KMT2D mutated Kabuki syndrome since she was 4 years old presented with acute lumbar pain and intermittent tactile hyposthenia of the feet. Spine magnetic resonance revealed a lumbar endocanalar mass. She underwent surgical resection of the lesion and histologic examination showed a tanycytic ependymoma (WHO grade II).

CONCLUSION

Kabuki syndrome is not considered a cancer predisposition syndrome. Nonetheless, a number of tumors have been reported in patients with Kabuki syndrome. Spinal ependymoma is a rare disease in the pediatric and young adult population. Whereas NF2 mutations are frequently associated to ependymoma such an association has never been described in Kabuki syndrome. To our knowledge this is the first case of ependymoma in a KMT2D mutated Kabuki syndrome patient. Despite KMT2D role in cancer has previously been described, no genetic data are available for previously reported Kabuki syndrome patients with tumors. Nonetheless, the association of two rare diseases raises the suspicion for a common determinant.

Identification of KMT2D and KDM6A mutations by exome sequencing in Korean patients with Kabuki syndrome

Kabuki syndrome (KS) (OMIM#147920) is a multiple congenital anomaly/mental retardation syndrome. Recently, pathogenic variants in KMT2D and KDM6A were identified as the causes of KS in 55.8-80.0% of patients. To elucidate further the molecular characteristics of Korean patients with KS, we screened a cohort of patients with clinically defined KS for mutations in KMT2D and KDM6A. Whole-exome sequencing and direct sequencing for validation were performed in 12 patients with a clinical suspicion of KS. KMT2D and KDM6A mutations were identified in 11 (91.7%) patients. No recurrent mutation was observed, and 10 out of the 11 mutations found were novel. KMT2D mutations were detected in 10 patients, including four small deletions or insertions and four nonsense and two missense mutations. One girl had a novel splice-site mutation in KDM6A. Each patient had a unique individual mutation. This is the first report of mutational analysis via exome sequencing in Korean patients with KS. Because the mutation-detection rate was high in this study, rigorous mutation analysis of KMT2D and KDM6A may be an important tool for the early diagnosis and genetic counseling of Korean patients with KS.

The H3K27me3 demethylase UTX in normal development and disease

In 2007, the Ubiquitously Transcribed Tetratricopeptide Repeat on chromosome X (UTX) was identified as a histone demethylase that specifically targets di- and tri-methyl groups on lysine 27 of histone H3 (H3K27me2/3). Since then, UTX has been proven essential during normal development, as it is critically required for correct reprogramming, embryonic development and tissue-specific differentiation. UTX is a member of the MLL2 H3K4 methyltransferase complex and its catalytic activity has been linked to regulation of HOX and RB transcriptional networks. In addition, an H3K27me2/3 demethylase independent function for UTX was uncovered in promoting general chromatin remodeling in concert with the BRG1-containing SWI/SNF remodeling complex. Constitutional inactivation of UTX causes a specific hereditary disorder called the Kabuki syndrome, whereas somatic loss of UTX has been reported in a variety of human cancers. Here, we compile the breakthrough discoveries made from the first disclosure of UTX as a histone demethylase till the identification of disease-related UTX mutations and specific UTX inhibitors.

Deletion of KDM6A, a histone demethylase interacting with MLL2, in three patients with Kabuki syndrome

Kabuki syndrome (KS) is a rare genetic disease that causes developmental delay and congenital anomalies. Since the identification of MLL2 mutations as the primary cause of KS, such mutations have been identified in 56%-76% of affected individuals, suggesting that there may be additional genes associated with KS. Here, we describe three KS individuals with de novo partial or complete deletions of an X chromosome gene, KDM6A, that encodes a histone demethylase that interacts with MLL2. Although KDM6A escapes X inactivation, we found a skewed X inactivation pattern, in which the deleted X chromosome was inactivated in the majority of the cells. This study identifies KDM6A mutations as another cause of KS and highlights the growing role of histone methylases and histone demethylases in multiple-congenital-anomaly and intellectual-disability syndromes.