Wiedemann-Steiner Research Articles

Identification of a novel frameshift variant in the KMT2A gene of a child with Wiedemann-Steiner syndrome

To analyze pathogenic variant s of KMT2A gene in a child with Wiedemann-Steiner syndrome (WDSTS) and provide reliable evidences for clinical diagnosis of WDSTS. Whole-DNAs were extracted from an 9 years-old boy and his parents. Trio-whole exome sequencing (trio-WES) was performed to identify candidate pathogenic variants that can explain the boy's condition and sanger sequencing was conducted to prove it. The impact of detected variants were predicted and validated by bioinformatics tools. A de novo frameshift variant c.10488dupG (p.Leu3498Thrfs*41) in exon 27 of KMT2A gene was detected and this de novo variant (PS2) had not been reported in the world previously. This frameshift variant was absent in major allele frequency databases (PM2) and had been predicted to be pathogenic based on MutationTaster. Through HomoloGene and CD-search system, the 3498 locus (Leu) in KMT2A protein, which was an important histone modifying enzyme that regulated gene expression in early embryonic development and encoded by the KMT2A gene, was predicted as a high conserved locus (PP3), and that replacement of Lue3498 may result in frame-shifts with premature termination in 3539 locus by introducing stop codon, causing deletion of multiple functional domains which all played important roles on histone modifications and recognition (PVS1+PM1). According to the American College of Medical Genetics and Genomics variant classification guideline, the variant c.10488dupG (p.Leu3498Thrfs*41) in KMT2A was classified as pathogenic variant (PVS1+PS2+PM1+PM2+PP3). The patient's condition may be attributed to the de novo frameshift variant c.10488dupG (p.Leu3498Thrfs*41) in KMT2A gene. This study reported a pathogenic KMT2A variant that had not been reported previously in WDSTS, it expanded the genotypic spectrums of KMT2A variants.

KMT2A: Umbrella Gene for Multiple Diseases.

KMT2A (Lysine methyltransferase 2A) is a member of the epigenetic machinery, encoding a lysine methyltransferase responsible for the transcriptional activation through lysine 4 of histone 3 (H3K4) methylation. KMT2A has a crucial role in gene expression, thus it is associated to pathological conditions when found mutated. KMT2A germinal mutations are associated to Wiedemann–Steiner syndrome and also in patients with initial clinical diagnosis of several other chromatinopathies (i.e., Coffin–Siris syndromes, Kabuki syndrome, Cornelia De Lange syndrome, Rubinstein–Taybi syndrome), sharing an overlapping phenotype. On the other hand, KMT2A somatic mutations have been reported in several tumors, mainly blood malignancies. Due to its evolutionary conservation, the role of KMT2A in embryonic development, hematopoiesis and neurodevelopment has been explored in different animal models, and in recent decades, epigenetic treatments for disorders linked to KMT2A dysfunction have been extensively investigated. To note, pharmaceutical compounds acting on tumors characterized by KMT2A mutations have been formulated, and even nutritional interventions for chromatinopathies have become the object of study due to the role of microbiota in epigenetic regulation.

Premature Loss of Deciduous Teeth as a Symptom of Systemic Disease: A Narrative Literature Review.

Background: Premature loss of primary teeth can occur as a consequence of dental trauma, neonatal tooth extraction, early childhood caries, or periodontal problems, or it can be a manifestation of systemic disease. This review aims to present systemic disorders that can lead to premature loss of deciduous teeth in children and to provide a comprehensive resource for clinical practice for both physicians and dentists. Methods: This study is a narrative review of original studies and case reports published in English and Polish between 1957 and 2021 that was conducted by searching electronic scientific resources: PubMed, Google Scholar, Web of Science, and Science Direct. The schema of the qualification process is represented by a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). In total, 196 articles were identified; after provisional assessment of the titles and abstracts by two reviewers, 46 were found to be relevant to the topic, including 1 review, 16 original papers, and 27 case reports regarding systemic disease resulting in premature tooth loss. Results: In this study, 16 systemic diseases were linked to premature primary tooth loss in children: Papillon–Lefèvre syndrome, mucocutaneous dyskeratosis, Coffin–Lowry syndrome, congenital adrenal hyperplasia, Langerhans cell histiocytosis, cherubism, hypophosphatasia, acatalasia, Chediak–Higashi syndrome, cyclic neutropenia, erythromelalgia, Down syndrome, Hajdu–Cheney syndrome, short bowel syndrome, leukocyte adhesion deficiency type 1 (LAD-1), and Wiedemann–Steiner syndrome (WSS).

Clinical Utility of a Unique Genome-Wide DNA Methylation Signature for KMT2A-Related Syndrome.

Wiedemann–Steiner syndrome (WDSTS) is a Mendelian syndromic intellectual disability (ID) condition associated with hypertrichosis cubiti, short stature, and characteristic facies caused by pathogenic variants in the KMT2A gene. Clinical features can be inconclusive in mild and unusual WDSTS presentations with variable ID (mild to severe), facies (typical or not) and other associated malformations (bone, cerebral, renal, cardiac and ophthalmological anomalies). Interpretation and classification of rare KMT2A variants can be challenging. A genome-wide DNA methylation episignature for KMT2A-related syndrome could allow functional classification of variants and provide insights into the pathophysiology of WDSTS. Therefore, we assessed genome-wide DNA methylation profiles in a cohort of 60 patients with clinical diagnosis for WDSTS or Kabuki and identified a unique highly sensitive and specific DNA methylation episignature as a molecular biomarker of WDSTS. WDSTS episignature enabled classification of variants of uncertain significance in the KMT2A gene as well as confirmation of diagnosis in patients with clinical presentation of WDSTS without known genetic variants. The changes in the methylation profile resulting from KMT2A mutations involve global reduction in methylation in various genes, including homeobox gene promoters. These findings provide novel insights into the molecular etiology of WDSTS and explain the broad phenotypic spectrum of the disease.

Analysis of gene variation and clinical characteristics of Wiedemann-Steiner syndrome

Objective: To summarize and analyze the clinical characteristics and gene mutations of 6 patients with Wiedemann-Steiner syndrome (WDSTS). Methods: To review and analyze the clinical data, including general conditions, clinical manifestations, growth hormone, cranial or pituitary gland magnetic resonance imaging (MRI),gene results and other data, 6 cases with WDSTS admitted to the Department of Endocrinology, Genetics and Metabolism of Jiangxi Provincial Children's Hospital and the Department of Child Care of Pingxiang Maternity and Child Care from April 2017 to February 2021 were recruited. Results: Of the 6 patients, 2 were male and 4 were female. The age of the first visit ranged from 1.0 to 11.2 years. All the 6 children presented with growth retardation and mental retardation and they all had typical facial dysmorphism and hypertrichosis (mainly on the back and limbs). Among them, case 5 had a growth hormone deficiency, and case 2 and 4 had abnormalities revealed by cranial MRI. Variations in KMT2A gene were identified in these 6 patients: c.10900+2T>C,c.10837C>T(p.Gln3613*), c.4332G>A(p.E1444E), c.2508dupC(p.W838Lfs*9), c.11695_11696delinsT(p.T3899Sfs*73), c.9915dupA (p.P3306Tfs*22).Among these variations, c.4332G>A, c.11695_11696delinsT and c.9915dupA were novel mutations. Therefore, the final diagnosis of these patients was WDSTS. Conclusions: Patients presented with short stature and mental retardation, typical facial dysmorphism and hypertrichosis should be considered WDSTS. Whole-exome sequencing plays an important role in disease diagnosis and genetic counseling.

Evaluation of immunological abnormalities in patients with rare syndromes

Recurrent infections are important problems in syndromic patients. This study aimed to evaluate immunological abnormalities in patients who presented with recurrent infections and were diagnosed with rare syndromes. This retrospective analysis included 14 patients with complaints of recurrent infections, all of whom were diagnosed with a rare syndrome. The study group consisted of patients with Aicardi syndrome, Brugada syndrome, Phelan- McDermid syndrome, trichothiodystrophy, LEOPARD syndrome, Prader-Willi syndrome, Seckel syndrome, trisomy 18 (Edwards' syndrome), Wiedemann-Steiner syndrome, West syndrome, Williams syndrome, 47,XYY syndrome, 16p13 deletion syndrome, and 13q1.3 deletion syndrome. Seven patients (50%) were girls and seven (50%) were boys (mean age, 56.7 ±32.9 months; median [range] age: 45.5 [27-153] months). There were high rates of consanguinity (50%), cesarean section delivery (71%), and hospitalization in the intensive care unit (78.5%). No patients had a family history of immunodeficiency. On admission, all patients exhibited humoral and/or cellular immune system abnormalities. During the follow-up period, all T-cell abnormalities were improved after immunoglobulin replacement therapy (IGRT), while B-cell abnormalities persisted. These findings suggested that the patients predominantly had antibody deficiencies associated with mild T-cell abnormalities because of recurrent infections. The rates of infections and hospitalizations were significantly reduced after IGRT (p < 0.001); the rate of intensive care unit admission also significantly decreased (from 78.5% to 21.4%). Two of the three oxygen-dependent patients exhibited improvement therein. IGRT was discontinued in two patients with significant clinical improvement during follow-up. An immunological evaluation should be considered in pediatric patients with rare syndromes and recurrent infections. IGRT may help to improve the prognoses of these patients.

Feeding disorder in a patient with Wiedemann-Steiner syndrome.

Feeding disorder in a patient with Wiedemann-Steiner syndrome.

EP291 - Expanding the genotypic and phenotypic spectrum in a diverse cohort of 104 individuals with Wiedemann-Steiner Syndrome

eP291 - Expanding the genotypic and phenotypic spectrum in a diverse cohort of 104 individuals with Wiedemann-Steiner Syndrome

Expanding the genotypic and phenotypic spectrum in a diverse cohort of 104 individuals with Wiedemann-Steiner syndrome.

Wiedemann-Steiner syndrome (WSS) is an autosomal dominant disorder caused by monoallelic variants in KMT2A and characterized by intellectual disability and hypertrichosis. We performed a retrospective, multicenter, observational study of 104 individuals with WSS from five continents to characterize the clinical and molecular spectrum of WSS in diverse populations, to identify physical features that may be more prevalent in White versus Black Indigenous People of Color individuals, to delineate genotype-phenotype correlations, to define developmental milestones, to describe the syndrome through adulthood, and to examine clinicians' differential diagnoses. Sixty-nine of the 82 variants (84%) observed in the study were not previously reported in the literature. Common clinical features identified in the cohort included: developmental delay or intellectual disability (97%), constipation (63.8%), failure to thrive (67.7%), feeding difficulties (66.3%), hypertrichosis cubiti (57%), short stature (57.8%), and vertebral anomalies (46.9%). The median ages at walking and first words were 20 months and 18 months, respectively. Hypotonia was associated with loss of function (LoF) variants, and seizures were associated with non-LoF variants. This study identifies genotype-phenotype correlations as well as race-facial feature associations in an ethnically diverse cohort, and accurately defines developmental trajectories, medical comorbidities, and long-term outcomes in individuals with WSS.

Wiedemann-Steiner syndrome due to novel nonsense variant of KMT2A gene in a case

To explore the genetic basis for a child with unexplained global developmental delay (GDD), seizure, and facial deformity. Whole exome sequencing (WES) was carried out for the patient. Candidate variants were verified by Sanger sequencing of the patient and his parents. WES revealed that the patient has carried a previously unreported de novo heterozygous nonsense c.4906C>T (p.Arg1636Ter) variant of the KMT2A gene, Based on the American College of Medical Genetics and Genomics standards and guidelines, the c.4906C>T variant of KMT2A gene was predicted to be pathogenic (PVS1+ PS2+ PM2+PP3). The heterozygous nonsense c.4906C>T (p.Arg1636Ter) variant of the KMT2A gene probably underlay the disease in the child. Above finding has enriched the spectrum of pathogenic variants of the KMT2A gene.

Broad neurodevelopmental features and cortical anomalies associated with a novel de novo KMT2A variant in Wiedemann−Steiner syndrome

Wiedemann-Steiner syndrome (WDSTS) is a rare genetic disorder including developmental delay/intellectual disability (DD/ID), hypertrichosis cubiti, short stature, and distinctive facial features, caused by mutation in KMT2A gene, which encodes a histone methyltransferase (H3K4) that regulates chromatin-mediated transcription. Different neurodevelopmental phenotypes have been described within the WDSTS spectrum, including a peculiar Autism Spectrum Disorder (ASDs) subtype in some affected individuals.Here, we report a 9-year-old Caucasian male found by next-generation panel sequencing to carry a novel heterozygous de novo KMT2A frameshift variant (NM_001197104.2:c.4433delG; p. Arg1478LeufsTer108). This boy presented a WDSTS phenotype associated with broad neurodevelopmental features, including an unusual speech difficulty (i.e., palilalia), and brain imaging studies revealed an array of cortical anomalies (e.g., frontal simplified gyration, focal frontal cortical dysplasia). These clinical and radiological observations expand the known WDSTS-related neurodevelopmental phenotypes and further strengthen the important role of KMT2A in brain function and cortical development.

Expanding the phenotype associated to KMT2A variants: overlapping clinical signs between Wiedemann\u2013Steiner and Rubinstein\u2013Taybi syndromes

Lysine-specific methyltransferase 2A (KMT2A) is responsible for methylation of histone H3 (K4H3me) and contributes to chromatin remodeling, acting as “writer” of the epigenetic machinery. Mutations in KMT2A were first reported in Wiedemann–Steiner syndrome (WDSTS). More recently, KMT2A variants have been described in probands with a specific clinical diagnosis comprised in the so-called chromatinopathies. Such conditions, including WDSTS, are a group of overlapping disorders caused by mutations in genes coding for the epigenetic machinery. Among them, Rubinstein–Taybi syndrome (RSTS) is mainly caused by heterozygous pathogenic variants in CREBBP or EP300. In this work, we used next generation sequencing (either by custom-made panel or by whole exome) to identify alternative causative genes in individuals with a RSTS-like phenotype negative to CREBBP and EP300 mutational screening. In six patients we identified different novel unreported variants in KMT2A gene. The identified variants are de novo in at least four out of six tested individuals and all of them display some typical RSTS phenotypic features but also WDSTS specific signs. This study reinforces the concept that germline variants affecting the epigenetic machinery lead to a shared molecular effect (alteration of the chromatin state) determining superimposable clinical conditions.

Clinical and molecular spectrum of Wiedemann-Steiner syndrome, an emerging member of the chromatinopathy family

Clinical and molecular spectrum of Wiedemann-Steiner syndrome, an emerging member of the chromatinopathy family

Mutually suppressive roles of KMT2A and KDM5C in behaviour, neuronal structure, and histone H3K4 methylation

Histone H3 lysine 4 methylation (H3K4me) is extensively regulated by numerous writer and eraser enzymes in mammals. Nine H3K4me enzymes are associated with neurodevelopmental disorders to date, indicating their important roles in the brain. However, interplay among H3K4me enzymes during brain development remains largely unknown. Here, we show functional interactions of a writer-eraser duo, KMT2A and KDM5C, which are responsible for Wiedemann-Steiner Syndrome (WDSTS), and mental retardation X-linked syndromic Claes-Jensen type (MRXSCJ), respectively. Despite opposite enzymatic activities, the two mouse models deficient for either Kmt2a or Kdm5c shared reduced dendritic spines and increased aggression. Double mutation of Kmt2a and Kdm5c clearly reversed dendritic morphology, key behavioral traits including aggression, and partially corrected altered transcriptomes and H3K4me landscapes. Thus, our study uncovers common yet mutually suppressive aspects of the WDSTS and MRXSCJ models and provides a proof of principle for balancing a single writer-eraser pair to ameliorate their associated disorders.

The phenotype-driven computational analysis yields clinical diagnosis for patients with atypical manifestations of known intellectual disability syndromes.

BackgroundDue to extensive clinical and genetic heterogeneity of intellectual disability (ID) syndromes, the process of diagnosis is very challenging even for expert clinicians. Despite recent advancements in molecular diagnostics methodologies, a significant fraction of ID patients remains without a clinical diagnosis.Methods, results, and conclusionsHere, in a prospective study on a cohort of 21 families (trios) with a child presenting with ID of unknown etiology, we executed phenotype‐driven bioinformatic analysis method, PhenIX, utilizing targeted next‐generation sequencing (NGS) data and Human Phenotype Ontology (HPO)‐encoded phenotype data. This approach resulted in clinical diagnosis for eight individuals presenting with atypical manifestations of Rubinstein–Taybi syndrome 2 (MIM 613684), Spastic Paraplegia 50 (MIM 612936), Wiedemann–Steiner syndrome (MIM 605130), Cornelia de Lange syndrome 2 (MIM 300590), Cerebral creatine deficiency syndrome 1 (MIM 300352), Glass Syndrome (MIM 612313), Mental retardation, autosomal dominant 31 (MIM 616158), and Bosch–Boonstra–Schaaf optic atrophy syndrome (MIM 615722).

Dental phenotype of multiple impacted supernumerary teeth in Wiedemann–Steiner syndrome

Wiedemann–Steiner syndrome (WSS) is a rare autosomal dominant disorder characterized by short stature, intellectual disability, developmental delay, hypertrichosis cubiti, and dysmorphic facial features (thick eyebrows with a lateral flare, long eyelashes, vertically narrow and downslanting palpebral fissures, and wide nasal bridge). Dental findings reported with this syndrome are premature eruption of dentition, malocclusion, hypodontia, cleft palate, and retrognathia. We report a 12-year-old boy with a heterozygous two-base pair deletion in exon 22 of the KMT2A gene, resulting in a frameshift and premature truncation of the protein 17 amino acids downstream to codon 1974. Our patient exhibited multiple impacted supernumerary teeth which have never been reported earlier. This extends the dental phenotypic spectrum of WSS. To the best of our knowledge, this is the first reported case from India.

Wiedemann-Steiner syndrome caused by KMT2A gene variation in one child

对北京儿童医院神经内科诊断的KMT2A基因变异导致的Wiedemann-Steiner综合征1例患儿的临床资料进行回顾性分析，患儿，男，1岁4个月，因发育迟缓伴多毛就诊，体质量6.5 kg，身长66 cm，头围42 cm，均小于健康同龄儿童的2个标准差，营养不良，发育落后，不能独走，不会说话，易激惹、好动，肘部及后背皮肤多毛，特殊面容，眉毛浓密、小眼裂、长睫毛、宽眼距、塌鼻梁、球状鼻、薄上唇，肾脏彩超示马蹄肾，右肾盂充盈；头颅磁共振成像示胼胝体压部短，颞极蛛网膜下腔宽，侧脑室后部变尖，枕骨大孔似略窄，全外显子组基因测序发现患儿携带KMT2A基因第27外显子c.7071delC杂合缺失移码变异，导致蛋白质改变为p.S2358Lfs*18，该变异国内外均未见报道。提示对于生长迟缓、发育落后、多毛及特殊面容患者应考虑Wiedemann-Steiner综合征，除考虑进行染色体数目或拷贝数检测外，还需考虑到检测与染色体修饰重构相关的基因。

Expanding the neurodevelopmental phenotypes of individuals with de novo KMT2A variants

De novo loss-of-function (LoF) variants in the KMT2A gene are associated with Wiedemann−Steiner Syndrome (WSS). Recently, de novo KMT2A variants have been identified in sequencing studies of cohorts of individuals with neurodevelopmental disorders (NDDs). However, most of these studies lack the detailed clinical information required to determine whether those individuals have isolated NDDs or WSS (i.e. syndromic NDDs). We performed thorough clinical and neurodevelopmental phenotyping on six individuals with de novo KMT2A variants. From these data, we found that all six patients met clinical criteria for WSS and we further define the neurodevelopmental phenotypes associated with KMT2A variants and WSS. In particular, we identified a subtype of Autism Spectrum Disorder (ASD) in five individuals, characterized by marked rigid, repetitive and inflexible behaviours, emotional dysregulation, externalizing behaviours, but relative social motivation. To further explore the clinical spectrum associated with KMT2A variants, we also conducted a meta-analysis of individuals with KMT2A variants reported in the published literature. We found that de novo LoF or missense variants in KMT2A were significantly more prevalent than predicted by a previously established statistical model of de novo mutation rate for KMT2A. Our genotype−phenotype findings better define the clinical spectrum associated with KMT2A variants and suggest that individuals with de novo LoF and missense variants likely have a clinically unrecognized diagnosis of WSS, rather than isolated NDD or ASD alone. This highlights the importance of a clinical genetic and neurodevelopmental assessment for individuals with such variants in KMT2A.

A novel deletion mutation in KMT2A identified in a child with ID/DD and blood eosinophilia

BackgroundThe KMT2A gene encoded lysine methyltransferase plays an essential role in regulating gene expression during early development and hematopoiesis. To date, 92 different mutations of KMT2A have been curated in the human gene mutation database (HGMD), resulting in Wiedemann-Steiner syndrome (WDSTS) and intellectual disability (ID)/developmental delay (DD).Case presentationIn this report, we present a de novo heterozygous deletion mutation [c.74delG; p. (Gly26Alafs*2)] in the KMT2A gene, which was identified by trio-based whole exome sequencing from a 5.5-year-old boy with ID/DD, stereotypic hand movements and blood eosinophilia. Many deleterious germline mutations of KMT2A have been documented to affect development of central nervous system, oral and craniofacial tissues, but not blood eosinophils.ConclusionsThis is the first report of a rare case with ID/DD as well as eosinophilia, resulting from a previously undescribed null mutation of KMT2A. Our findings expand the phenotypical spectrum in affected individuals with KMT2A mutations, and may shed some insight into the role of KMT2A in eosinophil metabolism.

Wiedemann-Steiner syndrome caused by novel mutation of KMT2A gene: one case report and literature review

Objective To analyze the clinical and biochemical, as well as genetic characteristics of a patient with Wiedemann-Steiner syndrome (WDSTS). Methods The clinical data of a patient with WDSTS were collected. The patient was treated with recombinant human growth hormone (rhGH) combined with gonadotrophine-releasing hormone agonist (GnRHa). Blood samples of the patient and her parents were taken for whole-Exome Sequencing (WES). Relevant literatures about KMT2A mutations were reviewed. Results The 5-year old girl presented with growth retardation, with height 100 cm (-2.4 SD), torpid reaction, and facial anomalies including low hairline, thick eyebrow and hair, hypertelorism, a wide nasal bridge. She had small and puffy hands and feet, excessive hair around back of neck, bilateral forearm and lower limbs. Her GH peak level was 26.6 ng/ml during GH stimulation test. She was re-examined at the age of 10.4 years, with severe short stature (120 cm/-3.58 SD) and a Tanner stage 2 of breast development. Her bone age was found to be approximately 11.4 years. Height increased from 120 cm at the age of 10.4 years to 147.3 cm after rhGH treatment combined with GnRHa for 2.5 years. rhGH therapy alone continued for 1.1 years and a height of 150 cm was reached at the age of 14.9 years, with bone age 14 years. Gene sequencing revealed a de novo frameshift mutation (c.10051delA, p. Thr3351Leufs*17) of exon 27 in KMT2A gene of the patient, but without any mutation in her parents. Through a literature review, seventy-one patients with WDSTS (including present case) presented with intellectual disability(70/71), facial anomalies (70/71), short stature (50/71), and hypertrichosis(39/71). Conclusion Patients presented with short stature, typical facial dysmorphism, intellectual disability, and hypertrichosis should be considered for WDSTS. The mutation p. Thr3351Leufs*17 in the KMT2A gene detected in our patient is a novel mutation. This is so far the first report of WDSTS patient who was successfully treated with a combination of GH and GnRHa at the onset of puberty to improve her adult height. Key words: Wiedemann-Steiner syndrome; KMT2A gene; Short stature; Hypertrichosis; Therapy