Bryant-Li-Bhoj syndrome (BLBS), which became OMIM-classified in 2022 (OMIM: 619720, 619721), is caused by germline variants in the two genes that encode histone H3.3 (H3-3A/H3F3A and H3-3B/H3F3B) [1-4]. This syndrome is characterized by developmental delay/intellectual disability, craniofacial anomalies, hyper/hypotonia, and abnormal neuroimaging [1, 5]. BLBS was initially categorized as a progressive neurodegenerative syndrome caused by de novo heterozygous variants in either H3-3A or H3-3B [1-4]. Here, we analyze the data of the 58 previously published individuals along 38 unpublished, unrelated individuals. In this larger cohort of 96 people, we identify causative missense, synonymous, and stop-loss variants. We also expand upon the phenotypic characterization by elaborating on the neurodevelopmental component of BLBS. Notably, phenotypic heterogeneity was present even amongst individuals harboring the same variant. To explore the complex phenotypic variation in this expanded cohort, the relationships between syndromic phenotypes with three variables of interest were interrogated: sex, gene containing the causative variant, and variant location in the H3.3 protein. While specific genotype-phenotype correlations have not been conclusively delineated, the results presented here suggest that the location of the variants within the H3.3 protein and the affected gene (H3-3A or H3-3B) contribute more to the severity of distinct phenotypes than sex. Since these variables do not account for all BLBS phenotypic variability, these findings suggest that additional factors may play a role in modifying the phenotypes of affected individuals. Histones are poised at the interface of genetics and epigenetics, highlighting the potential role for gene-environment interactions and the importance of future research.

• MeSH
• dítě MeSH
• dospělí MeSH
• fenotyp * MeSH
• histony * genetika   MeSH
• lidé MeSH
• mentální retardace genetika   patologie   MeSH
• mladiství MeSH
• neurodegenerativní nemoci genetika   patologie   MeSH
• neurovývojové poruchy genetika   patologie   MeSH
• předškolní dítě MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Syndrom intelektuálního postižení související s DYRK1A (DYRK1A-related intellectual disability syndrome) je autozomálně dominantní onemocnění charakterizované středním až těžkým intelektuálním postižením, zpožděním vývoje řeči, poruchou autistického spektra a mikrocefalií. Typické jsou kraniofaciální dysmorfie, potíže s krmením, malý vzrůst, hypertonie, poruchy chůze. V kojeneckém věku bývají často febrilní záchvaty, později vývoj epilepsie. Cílem našeho kazuistického sdělení je prezentace 3leté pacientky s tímto syndromem. U naší pacientky bylo vzhledem k vyčerpaným diagnostickým možnostem a neobjasněné příčině intelektuálního postižení provedeno celoexomové sekvenování (WES). Pomocí této metody jsme nalezli heterozygotní patogenní variantu p.R205* v genu DYRK1A, což umožnilo rychlé stanovení kauzální diagnózy. Lze tedy říct, že WES představuje účinný diagnostický nástroj pro detekci mutací, které jsou příčinou různých syndromů spojených s intelektuálním postižením.

DYRK1A-related intellectual disability syndrome is an autosomal dominant disorder characterized by intellectual disability including impaired speech development, autism spectrum disorder, and microcephaly. Affected individuals often have a clinically recognizable phenotype including typical craniofacial dysmorphism, feeding problems, hypertonia, short stature, gait disturbances, and foot anomalies. Other medical concerns relate to febrile seizures in infancy with later development of epilepsy. This case report aims to present a case of a three-year-old girl with DYRK1A syndrome. Since there were no additional diagnostic methods available and the cause of the intellectual disability remained unexplained, we decided to perform whole-exome sequencing (WES). WES led to the identification of heterozygous pathogenic variant p.R205* in DYRK1A gene and enabled us to reach a causal diagnosis in a reasonable time frame. We can conclude, that WES is an efficient diagnostic approach to identify causative genetic variants for syndromes associated with intellectual disability.

• Klíčová slova
• DYRK1A syndrom,
• MeSH
• diferenciální diagnóza MeSH
• komorbidita MeSH
• lidé MeSH
• mentální retardace * diagnóza   genetika   patologie   MeSH
• předškolní dítě MeSH
• protein-serin-threoninkinasy antagonisté a inhibitory   genetika   MeSH
• sekvenování exomu MeSH
• tyrosinkinasy antagonisté a inhibitory   genetika   MeSH
• Check Tag
• lidé MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH

5,10-Methylenetetrahydrofolate reductase (MTHFR) deficiency usually presents as a severe neonatal disease. This study aimed to characterize natural history, biological and molecular data, and response to treatment of patients with late-onset MTHFR deficiency. The patients were identified through the European Network and Registry for Homocystinuria and Methylation Defects and the Adult group of the French Society for Inherited Metabolic Diseases; data were retrospectively colleted. To identify juvenile to adult-onset forms of the disease, we included patients with a diagnosis established after the age of 10 years. We included 14 patients (median age at diagnosis: 32 years; range: 11-54). At onset (median age: 20 years; range 9-38), they presented with walking difficulties (n = 8), cognitive decline (n = 3) and/or seizures (n = 3), sometimes associated with mild mental retardation (n = 6). During the disease course, symptoms were almost exclusively neurological with cognitive dysfunction (93%), gait disorders (86%), epilepsy (71%), psychiatric symptoms (57%), polyneuropathy (43%), and visual deficit (43%). Mean diagnostic delay was 14 years. Vascular events were observed in 28% and obesity in 36% of the patients. One patient remained asymptomatic at the age of 55 years. Upon treatment, median total homocysteine decreased (from 183 μmol/L, range 69-266, to 90 μmol/L, range 20-142) and symptoms improved (n = 9) or stabilized (n = 4). Missense pathogenic variants in the C-terminal regulatory domain of the protein were over-represented compared to early-onset cases. Residual MTHFR enzymatic activity in skin fibroblasts (n = 4) was rather high (17%-58%). This series of patients with late-onset MTHFR deficiency underlines the still unmet need of a prompt diagnosis of this treatable disease.

• MeSH
• dítě MeSH
• dospělí MeSH
• epilepsie diagnóza   patologie   MeSH
• homocystinurie diagnóza   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mentální retardace diagnóza   patologie   MeSH
• methylentetrahydrofolátreduktasa (NADPH2) nedostatek   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• opožděná diagnóza MeSH
• psychotické poruchy diagnóza   patologie   MeSH
• retrospektivní studie MeSH
• svalová spasticita diagnóza   patologie   MeSH
• věk při počátku nemoci MeSH
• záchvaty diagnóza   patologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH

• MeSH
• dospělí MeSH
• genetické testování metody   MeSH
• lidé MeSH
• mentální retardace genetika   patologie   MeSH
• neurovývojové poruchy * genetika   MeSH
• novorozenec MeSH
• proteinfosfatasa 2C genetika   MeSH
• výsledek terapie MeSH
• vývojové poruchy u dětí genetika   patofyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• novorozenec MeSH
• ženské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH

• MeSH
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mentální retardace etiologie   klasifikace   komplikace   patologie   MeSH
• neurologické vyšetření * metody   MeSH
• novorozenec MeSH
• postura těla MeSH
• psychomotorický výkon MeSH
• reflex MeSH
• supinační poloha MeSH
• svalová hypertonie klasifikace   MeSH
• svalová hypotonie klasifikace   MeSH
• vývoj dítěte klasifikace   MeSH
• vývojové poruchy u dětí klasifikace   MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• přehledy MeSH

TDP2 encodes a 5'-tyrosyl DNA phosphodiesterase required for the efficient repair of double-strand breaks (DSBs) induced by the abortive activity of DNA topoisomerase II (TOP2). To date, only three homozygous variants in TDP2 have been reported in six patients from four unrelated pedigrees with spinocerebellar ataxia 23 (SCAR23). By whole-exome sequencing, we identified a novel TDP2 splice-site variant (c.636 + 3_636 + 6del) in two Italian siblings (aged 40 and 45) showing progressive ataxia, intellectual disability, speech delay, refractory seizures, and various physical anomalies. The variant caused exon 5 skipping with consequent nonsense-mediated mRNA decay and defective repair of TOP2-induced DSBs, as demonstrated by the functional assays on the patients' fibroblasts. Our findings further demonstrate the pathogenic role of TDP2 biallelic loss-of-function variants in SCAR23 pathogenesis. Considering the age of our patients, the oldest reported to date, and their extensive follow-up, our study delineates in more detail the clinical phenotype related to the loss of TDP2 activity.

• MeSH
• DNA vazebné proteiny genetika   MeSH
• dospělí MeSH
• fosfodiesterasy genetika   MeSH
• geny recesivní genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mentální retardace genetika   patologie   MeSH
• mutace ztráty funkce genetika   MeSH
• spinocerebelární ataxie genetika   patofyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

Birk Barel syndrome also known as KCNK9 imprinting syndrome is a rare developmental disorder associated with a loss-of-function variant in KCNK9, an imprinted gene with maternal expression on the 8th chromosome encoding the TASK3 (TWIK-related acidity inhibited K + -channel 3). Only two variants of KCNK9 have been associated with this condition before, both of them leading to the same amino-acid exchange p.Gly236Arg (Barel, 2008, Graham, 2016). We describe a case of a 17-year-old girl presenting with very similar phenotype and pure motor neuropathy with a novel variant c.710C > A: p.Ala237Asp (NM_001282534.1) in KCNK9 found by whole exome sequencing. Our case suggests that Birk Barel syndrome may not be caused only by variants leading to amino-acid exchange p.Gly236Arg but also by other missense variant in this gene and that peripheral motor neuropathy might be a feature of this syndrome.

• MeSH
• draslíkové kanály s dvoupórovou doménou genetika   MeSH
• genetická predispozice k nemoci * MeSH
• genomový imprinting genetika   MeSH
• kraniofaciální abnormality genetika   patologie   MeSH
• lidé MeSH
• mentální retardace genetika   patologie   MeSH
• missense mutace genetika   MeSH
• mladiství MeSH
• sekvence aminokyselin genetika   MeSH
• sekvenování exomu MeSH
• svalová hypotonie genetika   patologie   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

BACKGROUND AND AIM: To describe current diagnostic and therapeutic strategies in organic acidurias (OADs) and to evaluate their impact on the disease course allowing harmonisation. METHODS: Datasets of 567 OAD patients from the E-IMD registry were analysed. The sample includes patients with methylmalonic (MMA, n = 164), propionic (PA, n = 144) and isovaleric aciduria (IVA, n = 83), and glutaric aciduria type 1 (GA1, n = 176). Statistical analysis included description and recursive partitioning of diagnostic and therapeutic strategies, and odds ratios (OR) for health outcome parameters. For some analyses, symptomatic patients were divided into those presenting with first symptoms during (i.e. early onset, EO) or after the newborn period (i.e. late onset, LO). RESULTS: Patients identified by newborn screening (NBS) had a significantly lower median age of diagnosis (8 days) compared to the LO group (363 days, p < 0.001], but not compared to the EO group. Of all OAD patients 71 % remained asymptomatic until day 8. Patients with cobalamin-nonresponsive MMA (MMA-Cbl(-)) and GA1 identified by NBS were less likely to have movement disorders than those diagnosed by selective screening (MMA-Cbl(-): 10 % versus 39 %, p = 0.002; GA1: 26 % versus 73 %, p < 0.001). For other OADs, the clinical benefit of NBS was less clear. Reported age-adjusted intake of natural protein and calories was significantly higher in LO patients than in EO patients reflecting different disease severities. Variable drug combinations, ranging from 12 in MMA-Cbl(-) to two in isovaleric aciduria, were used for maintenance treatment. The effects of specific metabolic treatment strategies on the health outcomes remain unclear because of the strong influences of age at onset (EO versus LO), diagnostic mode (NBS versus selective screening), and the various treatment combinations used. CONCLUSIONS: NBS is an effective intervention to reduce time until diagnosis especially for LO patients and to prevent irreversible cerebral damage in GA1 and MMA-Cbl(-). Huge diversity of therapeutic interventions hampers our understanding of optimal treatment.

• MeSH
• dítě MeSH
• dospělí MeSH
• glutaryl-CoA-dehydrogenasa nedostatek   metabolismus   MeSH
• kojenec MeSH
• kyselina methylmalonová metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mentální retardace metabolismus   patologie   MeSH
• metabolické nemoci mozku vrozené metabolismus   patologie   MeSH
• metabolické nemoci mozku metabolismus   patologie   MeSH
• metabolické nemoci metabolismus   patologie   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• novorozenec MeSH
• novorozenecký screening metody   MeSH
• předškolní dítě MeSH
• věk při počátku nemoci MeSH
• vitamin B 12 metabolismus   MeSH
• vrozené poruchy metabolismu aminokyselin metabolismus   patologie   MeSH
• vrozené poruchy transportu aminokyselin metabolismus   patologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chromosome 17q21.31 microdeletion syndrome is a genomic disorder caused by a recurrent 600 kb long deletion. The deletion affects the region of a common inversion present in about 20% of Europeans. The inversion is associated with the H2 haplotype carrying additional low-copy repeats susceptible to non-allelic homologous recombination, and this haplotype is prone to deletion. No instances of 17q21.31 deletions inherited from an affected parent have been reported, and the deletions always affected a parental chromosome with the H2 haplotype. The syndrome is characterized clinically by intellectual disability, hypotonia, friendly behavior and specific facial dysmorphism with long face, large tubular or pear-shaped nose and bulbous nasal tip. We present monozygotic twin sisters showing the typical clinical picture of the syndrome. The phenotype of the sisters was very similar, with a slightly more severe presentation in Twin B. The 17q21.31 microdeletion was confirmed in both patients but in neither of their parents. Potential copy number differences between the genomes of the twins were subsequently searched using high-resolution single nucleotide polymorphism (SNP) and comparative genome hybridisation (CGH) arrays. However, these analyses identified no additional aberrations or genomic differences that could potentially be responsible for the subtle phenotypic differences. These could possibly be related to the more severe perinatal history of Twin B, or to the variable expressivity of the disorder. In accord with the expectations, one of the parents (the mother) was shown to carry the H2 haplotype, and the maternal allele of chromosome 17q21.31 was missing in the twins.

• MeSH
• chromozomální delece MeSH
• dospělí MeSH
• dvojčata monozygotní genetika   MeSH
• haplotypy * MeSH
• jednonukleotidový polymorfismus * MeSH
• lidé MeSH
• lidské chromozomy, pár 17 genetika   MeSH
• mentální retardace genetika   patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• studie na dvojčatech MeSH

• MeSH
• lidé MeSH
• mentální retardace * patologie   psychologie   rehabilitace   MeSH
• osoby s mentálním postižením * psychologie   rehabilitace   MeSH
• postoj MeSH
• sociální opora * MeSH
• sociální prostředí MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• komentáře MeSH