ABSTRACT
Misregulation of histone lysine methylation is associated with several human cancers and with human developmental disorders. DOT1L is an evolutionarily conserved gene encoding a lysine methyltransferase (KMT) that methylates histone 3 lysine-79 (H3K79) and was not previously associated with a Mendelian disease in OMIM. We have identified nine unrelated individuals with seven different de novo heterozygous missense variants in DOT1L through the Undiagnosed Disease Network (UDN), the SickKids Complex Care genomics project, and GeneMatcher. All probands had some degree of global developmental delay/intellectual disability, and most had one or more major congenital anomalies. To assess the pathogenicity of the DOT1L variants, functional studies were performed in Drosophila and human cells. The fruit fly DOT1L ortholog, grappa, is expressed in most cells including neurons in the central nervous system. The identified DOT1L variants behave as gain-of-function alleles in flies and lead to increased H3K79 methylation levels in flies and human cells. Our results show that human DOT1L and fly grappa are required for proper development and that de novo heterozygous variants in DOT1L are associated with a Mendelian disease.
Subject(s)
Congenital Abnormalities , Developmental Disabilities , Histone-Lysine N-Methyltransferase , Humans , Gain of Function Mutation , Histone-Lysine N-Methyltransferase/genetics , Histones/genetics , Histones/metabolism , Lysine , Methylation , Methyltransferases/genetics , Neoplasms/genetics , Drosophila/genetics , Drosophila Proteins/genetics , Developmental Disabilities/genetics , Congenital Abnormalities/geneticsABSTRACT
Acetylation of the lysine residues in histones and other DNA-binding proteins plays a major role in regulation of eukaryotic gene expression. This process is controlled by histone acetyltransferases (HATs/KATs) found in multiprotein complexes that are recruited to chromatin by the scaffolding subunit transformation/transcription domain-associated protein (TRRAP). TRRAP is evolutionarily conserved and is among the top five genes intolerant to missense variation. Through an international collaboration, 17 distinct de novo or apparently de novo variants were identified in TRRAP in 24 individuals. A strong genotype-phenotype correlation was observed with two distinct clinical spectra. The first is a complex, multi-systemic syndrome associated with various malformations of the brain, heart, kidneys, and genitourinary system and characterized by a wide range of intellectual functioning; a number of affected individuals have intellectual disability (ID) and markedly impaired basic life functions. Individuals with this phenotype had missense variants clustering around the c.3127G>A p.(Ala1043Thr) variant identified in five individuals. The second spectrum manifested with autism spectrum disorder (ASD) and/or ID and epilepsy. Facial dysmorphism was seen in both groups and included upslanted palpebral fissures, epicanthus, telecanthus, a wide nasal bridge and ridge, a broad and smooth philtrum, and a thin upper lip. RNA sequencing analysis of skin fibroblasts derived from affected individuals skin fibroblasts showed significant changes in the expression of several genes implicated in neuronal function and ion transport. Thus, we describe here the clinical spectrum associated with TRRAP pathogenic missense variants, and we suggest a genotype-phenotype correlation useful for clinical evaluation of the pathogenicity of the variants.
Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Autistic Disorder/etiology , Intellectual Disability/etiology , Mutation, Missense , Nuclear Proteins/genetics , Adolescent , Adult , Amino Acid Sequence , Autistic Disorder/metabolism , Autistic Disorder/pathology , Child , Child, Preschool , Female , Genetic Association Studies , Humans , Infant , Intellectual Disability/metabolism , Intellectual Disability/pathology , Male , Prognosis , Sequence Homology , Syndrome , Young AdultABSTRACT
PURPOSE: Lamins are the major component of nuclear lamina, maintaining structural integrity of the nucleus. Lamin A/C variants are well established to cause a spectrum of disorders ranging from myopathies to progeria, termed laminopathies. Phenotypes resulting from variants in LMNB1 and LMNB2 have been much less clearly defined. METHODS: We investigated exome and genome sequencing from the Deciphering Developmental Disorders Study and the 100,000 Genomes Project to identify novel microcephaly genes. RESULTS: Starting from a cohort of patients with extreme microcephaly, 13 individuals with heterozygous variants in the two human B-type lamins were identified. Recurrent variants were established to be de novo in nine cases and shown to affect highly conserved residues within the lamin É-helical rod domain, likely disrupting interactions required for higher-order assembly of lamin filaments. CONCLUSION: We identify dominant pathogenic variants in LMNB1 and LMNB2 as a genetic cause of primary microcephaly, implicating a major structural component of the nuclear envelope in its etiology and defining a new form of laminopathy. The distinct nature of this lamin B-associated phenotype highlights the strikingly different developmental requirements for lamin paralogs and suggests a novel mechanism for primary microcephaly warranting future investigation.
Subject(s)
Laminopathies , Microcephaly , Humans , Lamin Type B/genetics , Microcephaly/geneticsABSTRACT
Developmental and epileptic encephalopathy (DEE) is a group of conditions characterized by the co-occurrence of epilepsy and intellectual disability (ID), typically with developmental plateauing or regression associated with frequent epileptiform activity. The cause of DEE remains unknown in the majority of cases. We performed whole-genome sequencing (WGS) in 197 individuals with unexplained DEE and pharmaco-resistant seizures and in their unaffected parents. We focused our attention on de novo mutations (DNMs) and identified candidate genes containing such variants. We sought to identify additional subjects with DNMs in these genes by performing targeted sequencing in another series of individuals with DEE and by mining various sequencing datasets. We also performed meta-analyses to document enrichment of DNMs in candidate genes by leveraging our WGS dataset with those of several DEE and ID series. By combining these strategies, we were able to provide a causal link between DEE and the following genes: NTRK2, GABRB2, CLTC, DHDDS, NUS1, RAB11A, GABBR2, and SNAP25. Overall, we established a molecular diagnosis in 63/197 (32%) individuals in our WGS series. The main cause of DEE in these individuals was de novo point mutations (53/63 solved cases), followed by inherited mutations (6/63 solved cases) and de novo CNVs (4/63 solved cases). De novo missense variants explained a larger proportion of individuals in our series than in other series that were primarily ascertained because of ID. Moreover, these DNMs were more frequently recurrent than those identified in ID series. These observations indicate that the genetic landscape of DEE might be different from that of ID without epilepsy.
Subject(s)
Brain Diseases/genetics , Epilepsy/genetics , Mutation/genetics , Child , Child, Preschool , Female , Genome, Human/genetics , Genome-Wide Association Study/methods , Humans , Intellectual Disability/genetics , Male , Recurrence , Seizures/geneticsABSTRACT
Genomic knowledge and technology have developed rapidly over the last decade and increased our capabilities to diagnose and manage rare diseases. However, current genomic datasets lack ethnic diversity as many genomic studies have focused on participants of white European ancestry. Studies, such as the Deciphering Developmental Disorders study, have been available to participants of any ancestry but have been unsuccessful in recruiting diverse populations. The inclusion of diverse populations in exome and genome sequencing is important to ensure that clinical benefits of genomics advances are equally shared among all populations and to advance scientific knowledge. Our clinical and research experience with the British Pakistani population (the largest ethnic minority in Yorkshire and Humber, accounting for 4.3% of the population) has fostered the development of an innovative cultural competence framework to enhance the inclusion of diverse populations in clinical genomic research and service provision. The application of this framework has the potential to guide healthcare professionals to develop a wide range of competences, so they are ready to embrace genomic advances in order to improve health outcomes for all patients. This practice model will inform precision medicine and improve access of diverse populations to genomic studies. Although based upon work with the Pakistani population in the UK, it is anticipated that the model would be broadly applicable to all underrepresented populations across the world.
Subject(s)
Ethnicity/genetics , Genome, Human , Minority Groups , Cultural Competency , Humans , Precision Medicine , Rare Diseases/geneticsABSTRACT
The lipid phosphatase gene FIG4 is responsible for Yunis-Varón syndrome and Charcot-Marie-Tooth disease Type 4J, a peripheral neuropathy. We now describe four families with FIG4 variants and prominent abnormalities of central nervous system (CNS) white matter (leukoencephalopathy), with onset in early childhood, ranging from severe hypomyelination to mild undermyelination, in addition to peripheral neuropathy. Affected individuals inherited biallelic FIG4 variants from heterozygous parents. Cultured fibroblasts exhibit enlarged vacuoles characteristic of FIG4 dysfunction. Two unrelated families segregate the same G > A variant in the +1 position of intron 21 in the homozygous state in one family and compound heterozygous in the other. This mutation in the splice donor site of exon 21 results in read-through from exon 20 into intron 20 and truncation of the final 115 C-terminal amino acids of FIG4, with retention of partial function. The observed CNS white matter disorder in these families is consistent with the myelination defects in the FIG4 null mouse and the known role of FIG4 in oligodendrocyte maturation. The families described here the expanded clinical spectrum of FIG4 deficiency to include leukoencephalopathy.
Subject(s)
Alleles , Demyelinating Diseases/diagnosis , Demyelinating Diseases/genetics , Flavoproteins/genetics , Genetic Association Studies , Genetic Predisposition to Disease , Mutation , Phosphoric Monoester Hydrolases/genetics , Child , Child, Preschool , DNA Mutational Analysis , Demyelinating Diseases/metabolism , Fibroblasts/metabolism , Genotype , Humans , Inheritance Patterns , Magnetic Resonance Imaging , Male , Neuroimaging , Pedigree , PhenotypeABSTRACT
BACKGROUND: SOX11 is a transcription factor proposed to play a role in brain development. The relevance of SOX11 to human developmental disorders was suggested by a recent report of SOX11 mutations in two patients with Coffin-Siris syndrome. Here we further investigate the role of SOX11 variants in neurodevelopmental disorders. METHODS: We used array based comparative genomic hybridisation and trio exome sequencing to identify children with intellectual disability who have deletions or de novo point mutations disrupting SOX11. The pathogenicity of the SOX11 mutations was assessed using an in vitro gene expression reporter system. Loss-of-function experiments were performed in xenopus by knockdown of Sox11 expression. RESULTS: We identified seven individuals with chromosome 2p25 deletions involving SOX11. Trio exome sequencing identified three de novo SOX11 variants, two missense (p.K50N; p.P120H) and one nonsense (p.C29*). The biological consequences of the missense mutations were assessed using an in vitro gene expression system. These individuals had microcephaly, developmental delay and shared dysmorphic features compatible with mild Coffin-Siris syndrome. To further investigate the function of SOX11, we knocked down the orthologous gene in xenopus. Morphants had significant reduction in head size compared with controls. This suggests that SOX11 loss of function can be associated with microcephaly. CONCLUSIONS: We thus propose that SOX11 deletion or mutation can present with a Coffin-Siris phenotype.
Subject(s)
Abnormalities, Multiple/genetics , Face/abnormalities , Hand Deformities, Congenital/genetics , Intellectual Disability/genetics , Micrognathism/genetics , Neck/abnormalities , Neurodevelopmental Disorders/genetics , SOXC Transcription Factors/genetics , Sequence Deletion , Abnormalities, Multiple/physiopathology , Adolescent , Adult , Animals , Child , Child, Preschool , Face/physiopathology , Female , Gene Knockdown Techniques , Hand Deformities, Congenital/physiopathology , Humans , Intellectual Disability/physiopathology , Male , Microcephaly , Micrognathism/physiopathology , Neck/physiopathology , Neurodevelopmental Disorders/physiopathology , XenopusABSTRACT
Cerebro-Costo-Mandibular syndrome (CCMS) is a rare autosomal dominant condition comprising branchial arch-derivative malformations with striking rib-gaps. Affected patients often have respiratory difficulties, associated with upper airway obstruction, reduced thoracic capacity, and scoliosis. We describe a series of 12 sporadic and 4 familial patients including 13 infants/children and 3 adults. Severe micrognathia and reduced numbers of ribs with gaps are consistent findings. Cleft palate, feeding difficulties, respiratory distress, tracheostomy requirement, and scoliosis are common. Additional malformations such as horseshoe kidney, hypospadias, and septal heart defect may occur. Microcephaly and significant developmental delay are present in a small minority of patients. Key radiological findings are of a narrow thorax, multiple posterior rib gaps and abnormal costo-transverse articulation. A novel finding in 2 patients is bilateral accessory ossicles arising from the hyoid bone. Recently, specific mutations in SNRPB, which encodes components of the major spliceosome, have been found to cause CCMS. These mutations cluster in an alternatively spliced regulatory exon and result in altered SNRPB expression. DNA was available from 14 patients and SNRPB mutations were identified in 12 (4 previously reported). Eleven had recurrent mutations previously described in patients with CCMS and one had a novel mutation in the alternative exon. These results confirm the specificity of SNRPB mutations in CCMS and provide further evidence for the role of spliceosomal proteins in craniofacial and thoracic development.
Subject(s)
Abnormalities, Multiple/genetics , Cleft Palate/genetics , Intellectual Disability/genetics , Micrognathism/genetics , Ribs/abnormalities , snRNP Core Proteins/genetics , Abnormalities, Multiple/physiopathology , Adolescent , Child , Child, Preschool , Cleft Palate/complications , Cleft Palate/physiopathology , Exons , Female , Humans , Infant , Intellectual Disability/complications , Intellectual Disability/physiopathology , Male , Micrognathism/complications , Micrognathism/physiopathology , Mutation , Ribs/growth & development , Ribs/physiopathology , Scoliosis/complications , Scoliosis/genetics , Scoliosis/physiopathology , Spliceosomes/geneticsABSTRACT
BACKGROUND: Pallister-Killian syndrome is a rare, sporadic condition caused by mosaic tetrasomy of the short arm of chromosome 12 (12p). The main features are intellectual disability, seizures, dysmorphic features and a variety of congenital malformations. Most available information comes from individual case reports. We report the results of a British study into Pallister-Killian syndrome, which is the first to provide comprehensive data on a population-based sample. METHOD: A detailed phenotypical study was carried out in Great Britain. All individuals with Pallister-Killian syndrome were eligible to participate. Each participant underwent a structured history, developmental assessment and clinical examination. Buccal mucosal samples were analysed by interphase fluorescence in situ hybridization (FISH) and blood samples by array comparative genomic hybridization (CGH). Genotype-phenotype correlations were sought in these tissues and existing skin biopsy reports. RESULTS: Twenty-two patients with Pallister-Killian syndrome, ranging from 4â months to 31â years were recruited and comprehensive data on each obtained. The birth incidence was 5.1 per million live births. Array CGH only suggested the diagnosis in 15.8% but buccal FISH could have made the diagnosis in 75.0%. There was no genotype-phenotype correlation in any of the tissues studied. This study shows that the high birth weights and profound intellectual disability classically described in Pallister-Killian syndrome are not universal. Mild or moderate intellectual disability was present in 27.6% of this cohort and all birth weights were within 2.67SD of the mean. New features which have not previously been recognised as part of Pallister-Killian syndrome include anhydrosis/hypohydrosis and episodic hyperventilation, suggesting involvement of the autonomic system.
Subject(s)
Abnormalities, Multiple/genetics , Chromosome Disorders/epidemiology , Chromosomes, Human, Pair 12/genetics , Intellectual Disability/genetics , Phenotype , Tetrasomy/pathology , Abnormalities, Multiple/pathology , Chromosome Disorders/genetics , Chromosome Disorders/pathology , Comparative Genomic Hybridization , Humans , In Situ Hybridization, Fluorescence , Intellectual Disability/pathology , Mosaicism , Tetrasomy/genetics , United Kingdom/epidemiologySubject(s)
Immunologic Deficiency Syndromes/diagnosis , Lymphocytes/physiology , Neoplasm Proteins/genetics , Sequence Deletion/genetics , Stromal Interaction Molecule 1/genetics , Cells, Cultured , Child, Preschool , Cord Blood Stem Cell Transplantation , Eczema , Humans , Ichthyosis , Immunologic Deficiency Syndromes/genetics , Immunologic Deficiency Syndromes/therapy , Infant , Infections , Male , Pedigree , PhenotypeABSTRACT
Léri-Weill dyschondrosteosis is caused by heterozygous mutations in SHOX or its flanking sequences, including whole or partial gene deletions, point mutations within the coding sequence, and deletions of downstream regulatory elements. The same mutations when biallelic cause the more severe Langer Mesomelic dysplasia. Here, we report on a consanguineous family with a novel deletion downstream of SHOX in which homozygously deleted individuals have a phenotype intermediate between Léri-Weill dyschondrosteosis and Langer Mesomelic dysplasia while heterozygously deleted individuals are mostly asymptomatic. The deleted region is distal to all previously described 3' deletions, suggesting the presence of an additional regulatory element, deletions of which have a milder, variable phenotypic effect.
Subject(s)
Genetic Association Studies , Homeodomain Proteins/genetics , Homozygote , Phenotype , Regulatory Sequences, Nucleic Acid , Sequence Deletion , Adult , Aged , Comparative Genomic Hybridization , Consanguinity , Enhancer Elements, Genetic , Female , Growth Disorders/diagnosis , Growth Disorders/genetics , Humans , In Situ Hybridization, Fluorescence , Middle Aged , Osteochondrodysplasias/diagnosis , Osteochondrodysplasias/genetics , Pedigree , Short Stature Homeobox ProteinABSTRACT
Classical aniridia is a congenital and progressive panocular disorder almost exclusively caused by heterozygous loss-of-function variants at the PAX6 locus. We report nine individuals from five families with severe aniridia and/or microphthalmia (with no detectable PAX6 mutation) with ultrarare monoallelic missense variants altering the Arg51 codon of MAB21L1. These mutations occurred de novo in 3/5 families, with the remaining families being compatible with autosomal dominant inheritance. Mice engineered to carry the p.Arg51Leu change showed a highly-penetrant optic disc anomaly in heterozygous animals with severe microphthalmia in homozygotes. Substitutions of the same codon (Arg51) in MAB21L2, a close homolog of MAB21L1, cause severe ocular and skeletal malformations in humans and mice. The predicted nucleotidyltransferase function of MAB21L1 could not be demonstrated using purified protein with a variety of nucleotide substrates and oligonucleotide activators. Induced expression of GFP-tagged wildtype and mutant MAB21L1 in human cells caused only modest transcriptional changes. Mass spectrometry of immunoprecipitated protein revealed that both mutant and wildtype MAB21L1 associate with transcription factors that are known regulators of PAX6 (MEIS1, MEIS2 and PBX1) and with poly(A) RNA binding proteins. Arg51 substitutions reduce the association of wild-type MAB21L1 with TBL1XR1, a component of the NCoR complex. We found limited evidence for mutation-specific interactions with MSI2/Musashi-2, an RNA-binding proteins with effects on many different developmental pathways. Given that biallelic loss-of-function variants in MAB21L1 result in a milder eye phenotype we suggest that Arg51-altering monoallelic variants most plausibly perturb eye development via a gain-of-function mechanism.
Subject(s)
Aniridia , Microphthalmos , Humans , Animals , Mice , Microphthalmos/genetics , PAX6 Transcription Factor/genetics , Aniridia/genetics , Mutation, Missense , Heterozygote , Transcription Factors/genetics , Homeodomain Proteins/genetics , RNA-Binding Proteins/genetics , Eye Proteins/genetics , Intracellular Signaling Peptides and Proteins/geneticsABSTRACT
BACKGROUND: Variable size deletions affecting 12q12 have been found in individuals with neurodevelopmental disorders (NDDs) and distinct facial and physical features. For many genetic loci affected by deletions in individuals with NDDs, reciprocal duplications have been described. However, for the 12q12 region, there are no detailed descriptions of duplication cases in the literature. METHODS: We report a phenotypic description of a family with monozygotic twins diagnosed with NDDs, carrying a 9 Mb duplication at 12q12, and five other individuals with overlapping duplications ranging from 4.54 Mb up to 15.16 Mb. RESULTS: The duplication carriers had language delays, cognitive delays, and were diagnosed with autism spectrum disorder. Additionally, distinct facial features (e.g., high foreheads, deeply set eyes, short palpebral fissures, small ears, high nasal bridges, abnormalities of the nose tip, thin lips), large feet, and abnormalities in the digits were noted. We also describe incomplete penetrance of the NDD phenotypes among the individuals with 12q12 duplication. CONCLUSION: This case series expands our knowledge on this rare genetic aberration and suggests that large 12q12 duplications may increase the risk for developing NDDs.
Subject(s)
Abnormalities, Multiple/genetics , Autism Spectrum Disorder/genetics , Chromosome Duplication , Chromosomes, Human, Pair 12/genetics , Developmental Disabilities/genetics , Phenotype , Abnormalities, Multiple/pathology , Autism Spectrum Disorder/pathology , Developmental Disabilities/pathology , Humans , Infant , Male , Syndrome , Twins, MonozygoticABSTRACT
In the last 3 years de novo sequence variants in the ARID2 (AT-rich interaction domain 2) gene, a subunit of the SWI/SNF complex, have been linked to intellectual disabilities in 3 case reports including one which describes frameshift mutations in ARID2 in 2 patients with features resembling Coffin-Siris syndrome. Coffin-Siris syndrome (CSS) is a rare congenital syndrome characterized by intellectual deficit, coarse facial features and hypoplastic or absent fifth fingernails and/or toenails among other features. Mutations in a number of different genes encoding SWI/SNF chromatin remodelling complex proteins have been described but the underlying molecular cause remains unknown in approximately 40% of patients with CSS. Here we describe 7 unrelated individuals, 2 with deletions of the ARID2 region and 5 with de novo truncating mutations in the ARID2 gene. Similarities to CSS are evident. Although hypertrichosis and hypoplasia of the fifth finger nail and distal phalanx do not appear to be common in these patients, toenail hypoplasia and the presence of Wormian bones might support the involvement of ARID2.
Subject(s)
Abnormalities, Multiple/genetics , Face/abnormalities , Hand Deformities, Congenital/genetics , Intellectual Disability/genetics , Micrognathism/genetics , Neck/abnormalities , Phenotype , Transcription Factors/genetics , Abnormalities, Multiple/pathology , Adolescent , Child , Child, Preschool , Face/pathology , Female , Hand Deformities, Congenital/pathology , Humans , Intellectual Disability/pathology , Male , Micrognathism/pathology , Neck/pathologyABSTRACT
Marfan syndrome is an autosomal dominant condition, with manifestations mainly in the skeletal, ocular, and cardiovascular systems. The disorder is caused by mutations in fibrillin-1 gene (FBN1). The majority of these are family-specific point mutations, with a small number being predicted to cause exon-skipping. To date, there have only been five reports of in-frame exon deletions in FBN1, with the largest of these spanning three exons. Mosaicism is rarely recorded and has only been reported in the unaffected, or mildly affected, parents of probands. Here, we report on the clinical histories of two children with exon deletions in FBN1. Both have severe Marfan syndrome with significant signs in infancy. One patient has a deletion of exon 33, which has not previously been reported. The other has the largest reported deletion, which spans 37 exons, and also represents the first reported case of mosaicism in a patient with Marfan syndrome.
Subject(s)
Exons/genetics , Gene Deletion , Marfan Syndrome/genetics , Microfilament Proteins/genetics , Child, Preschool , Female , Fibrillin-1 , Fibrillins , Humans , Infant , Marfan Syndrome/diagnostic imaging , Marfan Syndrome/physiopathology , Radiography , Severity of Illness IndexABSTRACT
We present a patient with a novel heterozygous deletion of 7q11.22-q11.23. Standard cytogenetic analysis using the ELN cosmid 82C and the ELN/ LIMK1 cosmid 34B FISH probes suggested a diagnosis of Williams syndrome. Although he has supravalvular aortic stenosis and peripheral pulmonary artery stenosis, which are common in this condition, he does not have the clinical gestalt of Williams syndrome. 44k oligo array CGH analysis showed a 2.43 Mb deletion, encompassing the proximal 1.43 kb of the Williams syndrome critical region and extending approximately 1 Mb beyond it. The deletion of further genes outside the Williams syndrome critical region does not appear to be having a phenotypic effect at present.
Subject(s)
Base Pairing/genetics , Chromosomes, Human, Pair 7/genetics , Sequence Deletion , Comparative Genomic Hybridization , Gene Deletion , Humans , Infant , Male , Williams Syndrome/geneticsABSTRACT
Staphylococcal scalded skin syndrome (SSSS) is a rare toxin-mediated condition caused by Staphylococcus aureus, which causes blistering and desquamation of the skin. Between November 2005 and April 2006, four children were admitted to critical care beds in the South West Regional Paediatric Burns Unit because of SSSS affecting more than 50% of the body surface area. Details of these cases are presented, highlighting the potential severity of the condition. The cases also illustrate that fluid overload is a common complication of the condition, despite hypovolaemia being the more obvious risk, and that both hyponatraemia and leukopenia are frequent findings. These summaries clearly demonstrate the need for paediatric critical care in a tertiary burns unit for children with SSSS affecting a large proportion of the body surface area. The cluster of admissions prompted us to write a management protocol for children with severe SSSS and a summary of this is provided. Most children with SSSS will initially present to general paediatric units, where mild cases will be managed, but severe cases should be promptly referred to a tertiary paediatric burns unit for multi-disciplinary care in a critical care environment.
Subject(s)
Critical Care/methods , Staphylococcal Scalded Skin Syndrome/therapy , Analgesia/methods , Bandages , Burn Units , Child , Child, Preschool , Enteral Nutrition/methods , Female , Fluid Therapy/methods , Humans , Hyponatremia/etiology , Hyponatremia/therapy , Length of Stay/statistics & numerical data , Leukocyte Count , Male , Patient Care Team , Staphylococcal Scalded Skin Syndrome/diagnosis , Staphylococcal Scalded Skin Syndrome/pathology , Water-Electrolyte Imbalance/etiology , Water-Electrolyte Imbalance/therapyABSTRACT
Tatton-Brown-Rahman syndrome (TBRS; OMIM 615879), also known as the DNMT3A-overgrowth syndrome, is an overgrowth intellectual disability syndrome first described in 2014 with a report of 13 individuals with constitutive heterozygous DNMT3A variants. Here we have undertaken a detailed clinical study of 55 individuals with de novoDNMT3A variants, including the 13 previously reported individuals. An intellectual disability and overgrowth were reported in >80% of individuals with TBRS and were designated major clinical associations. Additional frequent clinical associations (reported in 20-80% individuals) included an evolving facial appearance with low-set, heavy, horizontal eyebrows and prominent upper central incisors; joint hypermobility (74%); obesity (weight ³2SD, 67%); hypotonia (54%); behavioural/psychiatric issues (most frequently autistic spectrum disorder, 51%); kyphoscoliosis (33%) and afebrile seizures (22%). One individual was diagnosed with acute myeloid leukaemia in teenage years. Based upon the results from this study, we present our current management for individuals with TBRS.
ABSTRACT
ABSTRACT: Pathogenic variants in Paired-Like Homeobox 2B (PHOX2B) gene cause congenital central hypoventilation syndrome (CCHS), a rare disorder of the nervous system characterized by absent or reduced ventilatory response to hypoxia and hypercapnia. The focus of management in CCHS is optimizing ventilation. Thus far, no medication has proved effective in improving ventilation. Most CCHS cases are caused by polyalanine repeat expansion mutations. Non-polyalanine repeat expansion mutations are the cause in 8% of cases and result in a more severe clinical presentation. PHOX2B has 3 exons. Exon 3 of PHOX2B is the most common location for CCHS-causing mutations. Thus far, only 9 CCHS-causing mutations have been reported in exon 1, 8 of which were nonsense mutations. We report a child with CCHS who was found to have a novel heterozygous missense variant in exon 1; c.95A > T. Improvement in his apneic episodes was observed following treatment with carbamazepine.
Subject(s)
Carbamazepine/therapeutic use , Cytochrome P-450 CYP3A Inducers/therapeutic use , Homeodomain Proteins/genetics , Hypoventilation/congenital , Mutation, Missense/genetics , Sleep Apnea, Central/drug therapy , Transcription Factors/genetics , Child, Preschool , Humans , Hypoventilation/drug therapy , Hypoventilation/genetics , Infant , Male , Sleep Apnea, Central/genetics , Treatment OutcomeABSTRACT
We report on seven novel patients with a submicroscopic 22q12 deletion. The common phenotype constitutes a contiguous gene deletion syndrome on chromosome 22q12.1q12.2, featuring NF2-related schwannoma of the vestibular nerve, corpus callosum agenesis and palatal defects. Combining our results with the literature, eight patients are recorded with palatal defects in association with haploinsufficiency of 22q12.1, including the MN1 gene. These observations, together with the mouse expression data and the finding of craniofacial malformations including cleft palate in a Mn1-knockout mouse model, suggest that this gene is a candidate gene for cleft palate in humans.