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Clinics and Practice May 2024Tatton-Brown-Rahman syndrome is a rare autosomal dominant hereditary disease caused by pathogenic variants in the gene, which is an important participant in epigenetic...
Tatton-Brown-Rahman syndrome is a rare autosomal dominant hereditary disease caused by pathogenic variants in the gene, which is an important participant in epigenetic regulation, especially during embryonic development, and is highly expressed in all tissues. The main features of the syndrome are high growth, macrocephaly, intellectual disability, and facial dysmorphic features. We present a clinical case of Tatton-Brown-Rahman syndrome in a ten-year-old boy with macrocephaly with learning difficulties, progressive eye impairment, and fatigue suspected by a deep learning-based diagnosis assistance system, Face2Gene. The proband underwent whole-exome sequencing, which revealed a recurrent nonsense variant in the 12th exon of the , leading to the formation of a premature stop codon-NM_022552.5:c.1443C>A (p.Tyr481Ter), in a heterozygous state. This variant was not found in parents, confirming its de novo status. The patient case described here contributes to the understanding of the clinical diversity of Tatton-Brown-Raman syndrome with a mild clinical presentation that expands the phenotypic spectrum of the syndrome. We report the first recurrent nonsense variant in the gene, suggesting a mutational hot-spot. Differential diagnoses of this syndrome with Sotos syndrome, Weaver syndrome, and Cowden syndrome, as well as molecular confirmation, are extremely important, since the presence of certain types of pathogenic variants in the gene significantly increases the risk of developing acute myeloid leukemia.
PubMed: 38804405
DOI: 10.3390/clinpract14030073 -
International Journal of Molecular... May 2024Macrocephaly, characterized by an abnormally large head circumference, often co-occurs with distinctive finger changes, presenting a diagnostic challenge for clinicians.... (Review)
Review
Macrocephaly, characterized by an abnormally large head circumference, often co-occurs with distinctive finger changes, presenting a diagnostic challenge for clinicians. This review aims to provide a current synthetic overview of the main acquired and genetic etiologies associated with macrocephaly and finger changes. The genetic cause encompasses several categories of diseases, including bone marrow expansion disorders, skeletal dysplasias, ciliopathies, inherited metabolic diseases, RASopathies, and overgrowth syndromes. Furthermore, autoimmune and autoinflammatory diseases are also explored for their potential involvement in macrocephaly and finger changes. The intricate genetic mechanisms involved in the formation of cranial bones and extremities are multifaceted. An excess in growth may stem from disruptions in the intricate interplays among the genetic, epigenetic, and hormonal factors that regulate human growth. Understanding the underlying cellular and molecular mechanisms is important for elucidating the developmental pathways and biological processes that contribute to the observed clinical phenotypes. The review provides a practical approach to delineate causes of macrocephaly and finger changes, facilitate differential diagnosis and guide for the appropriate etiological framework. Early recognition contributes to timely intervention and improved outcomes for affected individuals.
Topics: Humans; Megalencephaly; Fingers
PubMed: 38791606
DOI: 10.3390/ijms25105567 -
Genes Apr 2024Infantile onset transient hypomyelination (IOTH) is a rare form of leukodystrophy that is associated with transient motor impairment and delayed central nervous system...
Infantile onset transient hypomyelination (IOTH) is a rare form of leukodystrophy that is associated with transient motor impairment and delayed central nervous system myelination. Here, we report a case of a new mutation in the transmembrane protein 63A () gene identified using Whole-Exome Sequencing (WES) in an 8.5-year-old boy with clinical symptoms similar to IOTH. The patient exhibited a mild developmental delay, including hypotonia and delayed motor milestones, as well as some notable phenotypic characteristics, such as macrocephaly and macrosomia. Despite the absence of early neuroimaging, genetic testing revealed a paternally inherited variant in (NM_14698.3:c.220A>T;p:(Arg74*)), potentially linked to infantile transient hypomyelinating leukodystrophy type 19. Our findings in this study and the patient's favorable clinical course underscore the potential for successful myelination even with delayed initiation and may contribute to a better understanding of the genotype-phenotype correlation in IOTH, emphasizing the importance of genetic analysis in unresolved developmental delay cases and providing critical insights for accurate diagnosis, prognosis and potential therapeutic strategies in rare leukodystrophies.
Topics: Humans; Male; Membrane Proteins; Child; Codon, Nonsense; Exome Sequencing; Heterozygote; Hereditary Central Nervous System Demyelinating Diseases; Genetic Association Studies
PubMed: 38790154
DOI: 10.3390/genes15050525 -
PLoS Biology May 2024Autism spectrum disorders (ASD) frequently accompany macrocephaly, which often involves hydrocephalic enlargement of brain ventricles. Katnal2 is a...
Autism spectrum disorders (ASD) frequently accompany macrocephaly, which often involves hydrocephalic enlargement of brain ventricles. Katnal2 is a microtubule-regulatory protein strongly linked to ASD, but it remains unclear whether Katnal2 knockout (KO) in mice leads to microtubule- and ASD-related molecular, synaptic, brain, and behavioral phenotypes. We found that Katnal2-KO mice display ASD-like social communication deficits and age-dependent progressive ventricular enlargements. The latter involves increased length and beating frequency of motile cilia on ependymal cells lining ventricles. Katnal2-KO hippocampal neurons surrounded by enlarged lateral ventricles show progressive synaptic deficits that correlate with ASD-like transcriptomic changes involving synaptic gene down-regulation. Importantly, early postnatal Katnal2 re-expression prevents ciliary, ventricular, and behavioral phenotypes in Katnal2-KO adults, suggesting a causal relationship and a potential treatment. Therefore, Katnal2 negatively regulates ependymal ciliary function and its deletion in mice leads to ependymal ciliary hyperfunction and hydrocephalus accompanying ASD-related behavioral, synaptic, and transcriptomic changes.
Topics: Animals; Male; Mice; Autism Spectrum Disorder; Behavior, Animal; Cilia; Disease Models, Animal; Ependyma; Hippocampus; Hydrocephalus; Katanin; Mice, Inbred C57BL; Mice, Knockout; Neurons; Phenotype; Synapses; Transcriptome
PubMed: 38718086
DOI: 10.1371/journal.pbio.3002596 -
Clinical Epigenetics May 2024Temple syndrome (TS14) is a rare imprinting disorder caused by maternal UPD14, imprinting defects or paternal microdeletions which lead to an increase in the maternal...
BACKGROUND
Temple syndrome (TS14) is a rare imprinting disorder caused by maternal UPD14, imprinting defects or paternal microdeletions which lead to an increase in the maternal expressed genes and a silencing the paternally expressed genes in the 14q32 imprinted domain. Classical TS14 phenotypic features include pre- and postnatal short stature, small hands and feet, muscular hypotonia, motor delay, feeding difficulties, weight gain, premature puberty along and precocious puberty.
METHODS
An exon array comparative genomic hybridization was performed on a patient affected by psychomotor and language delay, muscular hypotonia, relative macrocephaly, and small hand and feet at two years old. At 6 years of age, the proband presented with precocious thelarche. Genes dosage and methylation within the 14q32 region were analyzed by MS-MLPA. Bisulfite PCR and pyrosequencing were employed to quantification methylation at the four known imprinted differentially methylated regions (DMR) within the 14q32 domain: DLK1 DMR, IG-DMR, MEG3 DMR and MEG8 DMR.
RESULTS
The patient had inherited a 69 Kb deletion, encompassing the entire DLK1 gene, on the paternal allele. Relative hypermethylation of the two maternally methylated intervals, DLK1 and MEG8 DMRs, was observed along with normal methylation level at IG-DMR and MEG3 DMR, resulting in a phenotype consistent with TS14. Additional family members with the deletion showed modest methylation changes at both the DLK1 and MEG8 DMRs consistent with parental transmission.
CONCLUSION
We describe a girl with clinical presentation suggestive of Temple syndrome resulting from a small paternal 14q32 deletion that led to DLK1 whole-gene deletion, as well as hypermethylation of the maternally methylated DLK1-DMR.
Topics: Humans; Calcium-Binding Proteins; DNA Methylation; Chromosomes, Human, Pair 14; Intercellular Signaling Peptides and Proteins; Genomic Imprinting; Membrane Proteins; Child; Male; Comparative Genomic Hybridization; Female; Chromosome Deletion; Child, Preschool; Phenotype; Abnormalities, Multiple; Imprinting Disorders; Muscle Hypotonia; Facies
PubMed: 38715103
DOI: 10.1186/s13148-024-01652-8 -
Cell Reports. Medicine May 2024The size of the human head is highly heritable, but genetic drivers of its variation within the general population remain unmapped. We perform a genome-wide association...
The size of the human head is highly heritable, but genetic drivers of its variation within the general population remain unmapped. We perform a genome-wide association study on head size (N = 80,890) and identify 67 genetic loci, of which 50 are novel. Neuroimaging studies show that 17 variants affect specific brain areas, but most have widespread effects. Gene set enrichment is observed for various cancers and the p53, Wnt, and ErbB signaling pathways. Genes harboring lead variants are enriched for macrocephaly syndrome genes (37-fold) and high-fidelity cancer genes (9-fold), which is not seen for human height variants. Head size variants are also near genes preferentially expressed in intermediate progenitor cells, neural cells linked to evolutionary brain expansion. Our results indicate that genes regulating early brain and cranial growth incline to neoplasia later in life, irrespective of height. This warrants investigation of clinical implications of the link between head size and cancer.
Topics: Humans; Genome-Wide Association Study; Head; Neoplasms; Female; Male; Polymorphism, Single Nucleotide; Genetic Variation; Organ Size; Signal Transduction; Adult; Genetic Predisposition to Disease
PubMed: 38703765
DOI: 10.1016/j.xcrm.2024.101529 -
International Dental Journal May 2024Patients with PTEN hamartoma tumour syndrome (PHTS) have an increased risk of developing cancer due to a pathogenic germline variant in the PTEN tumour suppressor gene....
AIMS
Patients with PTEN hamartoma tumour syndrome (PHTS) have an increased risk of developing cancer due to a pathogenic germline variant in the PTEN tumour suppressor gene. Early recognition of PHTS facilitates initiation of cancer surveillance which is highly effective in preventing the development of advanced malignancies. PHTS is rare and due to its varied phenotype, even within families, oral abnormalities may be a valuable tool in the identification of these patients at an early stage before cancer development.
MATERIALS AND METHODS
Between 1997 and 2020, phenotypic characteristics were evaluated in 81 paediatric (median age: 9 years) and 86 adult (median age: 40 years) PHTS patients by one of 2 medical experts during yearly surveillance visits at a Dutch PHTS expertise centre. Oral features evaluated included gingival hypertrophy, oral papillomas, and high palate (in adults).
RESULTS
Within adults, gingival hypertrophy was present in 94%, oral papillomas in 88%, and a high palate in 89%. All adult patients had at least one of these oral features, and 99% showed at least 2 oral features. Oral features were less common in paediatric patients, especially under 11 years of age. Gingival hypertrophy was observed in 44% and oral papillomas in 54% of paediatric patients.
CONCLUSIONS
The presence of 2 or 3 oral features may indicate PHTS in adults or adolescents, especially if macrocephaly is present. Dental professionals are well-positioned to recognise these oral manifestations could be related to PHTS. They can initiate an overall clinical assessment of the patient by alerting the patient's medical practitioner of the findings and the possible need for genetic testing. This could significantly improve outcomes, including life expectancy, for patients and possibly for their relatives.
CLINICAL RELEVANCE
Dental professionals are ideally placed to recognise oral features and initiate early assessment of PHTS which could significantly improve patient outcomes.
PubMed: 38697906
DOI: 10.1016/j.identj.2024.04.014 -
Genes Mar 2024O'Donnell-Luria-Rodan (ODLURO) syndrome is an autosomal dominant disorder caused by mutations in the gene. The clinical phonotype of the affected individuals is...
O'Donnell-Luria-Rodan (ODLURO) syndrome is an autosomal dominant disorder caused by mutations in the gene. The clinical phonotype of the affected individuals is typically characterized by global developmental delay, autism, epilepsy, hypotonia, macrocephaly, and very mild dysmorphic facial features. In this report, we describe the case of a 6-year-old boy with ODLURO syndrome who is a carrier of the synonymous mutation c.186G>A (p.Ala62=) in the gene, predicted to alter splicing by in silico tools. Given the lack of functional studies on the c.186G>A variant, in order to assess its potential functional effect, we sequenced the patient's cDNA demonstrating its impact on the mechanism of splicing. To the best of our knowledge, our patient is the second to date reported carrying this synonymous mutation, but he is the first whose functional investigation has confirmed the deleterious consequence of the variant, resulting in exon 4 skipping. Additionally, we suggest a potential etiological mechanism that could be responsible for the aberrant splicing mechanism in .
Topics: Child; Humans; Male; Autistic Disorder; Developmental Disabilities; DNA-Binding Proteins; Intellectual Disability; Megalencephaly; Phenotype; RNA Splicing; Silent Mutation
PubMed: 38674365
DOI: 10.3390/genes15040430 -
Journal of Clinical Medicine Apr 2024Sotos syndrome is a genetic disorder caused by gene (nuclear receptor binding SET domain containing protein 1) variants and characterized by overgrowth, macrocephaly,... (Review)
Review
Sotos syndrome is a genetic disorder caused by gene (nuclear receptor binding SET domain containing protein 1) variants and characterized by overgrowth, macrocephaly, learning disabilities, and co-occurring neuropsychiatric symptoms. Literature sources published in 2002-2023 were selected and analyzed from PubMed and Google Scholar databases. Neuropsychiatric symptoms are observed among children and adolescents with Sotos syndrome. The majority have intellectual disabilities or borderline intellect. Verbal IQ is higher than performance IQ. Individuals display difficulties in expressing language. Aggression is reported by parents. Children express autistic behavior, ADHD, anxiety based on phobias, and early bedtime-wake times. Sotos syndrome is associated with neuropsychiatric disorders in children. Slow intellectual and language development, aggressive outbursts, anxiety, autism spectrum disorder, and hyperactivity are present in the newest studies. Comprehensive assistance is needed for Sotos syndrome patients in responding to areas of difficulty. There is still a lack of research on the developmental characteristics of these children and the possibilities of improving psychosocial adaptation by providing multidisciplinary long-term medical, educational, and social care.
PubMed: 38673476
DOI: 10.3390/jcm13082204