• MeSH
• psychologické testy MeSH

Both gain- and loss-of-function mutations have recently implicated HCFC1 in neurodevelopmental disorders. Here, we extend our previous HCFC1 over-expression studies by employing short hairpin RNA to reduce the expression of Hcfc1 in embryonic neural cells. We show that in contrast to over-expression, loss of Hcfc1 favoured proliferation of neural progenitor cells at the expense of differentiation and promoted axonal growth of post-mitotic neurons. To further support the involvement of HCFC1 in neurological disorders, we report two novel HCFC1 missense variants found in individuals with intellectual disability (ID). One of these variants, together with three previously reported HCFC1 missense variants of unknown pathogenicity, were functionally assessed using multiple cell-based assays. We show that three out of the four variants tested result in a partial loss of HCFC1 function. While over-expression of the wild-type HCFC1 caused reduction in HEK293T cell proliferation and axonal growth of neurons, these effects were alleviated upon over-expression of three of the four HCFC1 variants tested. One of these partial loss-of-function variants disrupted a nuclear localization sequence and the resulting protein displayed reduced ability to localize to the cell nucleus. The other two variants displayed negative effects on the expression of the HCFC1 target gene MMACHC, which is responsible for the metabolism of cobalamin, suggesting that these individuals may also be susceptible to cobalamin deficiency. Together, our work identifies plausible cellular consequences of missense HCFC1 variants and identifies likely and relevant disease mechanisms that converge on embryonic stages of brain development.

• MeSH
• aktivní transport - buněčné jádro MeSH
• buněčná diferenciace genetika   MeSH
• exprese genu MeSH
• faktor C1 hostitelské buňky chemie   genetika   metabolismus   MeSH
• HEK293 buňky MeSH
• kultivované buňky MeSH
• lidé MeSH
• malá interferující RNA genetika   MeSH
• mentální retardace genetika   MeSH
• mozek cytologie   embryologie   MeSH
• mutace * MeSH
• myši MeSH
• nervové kmenové buňky cytologie   metabolismus   MeSH
• proliferace buněk MeSH
• RNA interference MeSH
• rodokmen MeSH
• sekvence aminokyselin MeSH
• substituce aminokyselin MeSH
• transdukce genetická MeSH
• transportní proteiny genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A somatic mutation of the human leukocyte antigen (HLA)-A gene revealed in tumour cells of acute myelogenous leukemia (AML) is described. A patient with AML and her siblings were routinely typed for HLA in order to find a suitable donor for haematopoietic stem cell transplantation. Sequencing-based typing of the initial patient's sample characterized by high proportion of blasts revealed unknown G/A exchange at position 781 of the HLA-A gene (exon 4) associated with HLA-A*02:01 allele. Importantly, this G781A variant was completely absent in the patient's remission sample obtained after the clearance of blasts. Our results are a reminder that HLA mutations in tumour cells may interfere with routine HLA typing and should always be considered, namely, in patients with haematological malignancies.

• MeSH
• akutní myeloidní leukemie genetika   patologie   terapie   MeSH
• alely MeSH
• bodová mutace * MeSH
• dospělí MeSH
• exony genetika   MeSH
• HLA-A2 antigen genetika   MeSH
• indukce remise MeSH
• lidé MeSH
• missense mutace * MeSH
• molekulární sekvence - údaje MeSH
• nádorové kmenové buňky chemie   MeSH
• sekvence nukleotidů MeSH
• sourozenci MeSH
• substituce aminokyselin MeSH
• testování histokompatibility MeSH
• transplantace hematopoetických kmenových buněk MeSH
• zárodečné mutace MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH

OBJECTIVE: To identify the etiology of a novel, heritable encephalopathy in a small group of patients. METHODS: Magnetic resonance imaging (MRI) pattern analysis was used to select patients with the same pattern. Homozygosity mapping and whole exome sequencing (WES) were performed to find the causal gene mutations. RESULTS: Seven patients from 4 families (2 consanguineous) were identified with a similar MRI pattern characterized by T2 signal abnormalities and diffusion restriction in the posterior limb of the internal capsule, often also optic radiation, brainstem tracts, and cerebellar white matter, in combination with delayed myelination and progressive brain atrophy. Patients presented with early infantile onset encephalopathy characterized by progressive microcephaly, seizures, variable cardiac defects, and early death. Metabolic testing was unrevealing. Single nucleotide polymorphism array revealed 1 overlapping homozygous region on chromosome 20 in the consanguineous families. In all patients, WES subsequently revealed recessive predicted loss of function mutations in ITPA, encoding inosine triphosphate pyrophosphatase (ITPase). ITPase activity in patients' erythrocytes and fibroblasts was severely reduced. INTERPRETATION: Until now ITPA variants have only been associated with adverse reactions to specific drugs. This is the first report associating ITPA mutations with a human disorder. ITPase is important in purine metabolism because it removes noncanonical nucleotides from the cellular nucleotide pool. Toxicity of accumulated noncanonical nucleotides, leading to neuronal apoptosis and interference with proteins normally using adenosine triphosphate/guanosine triphosphate, probably explains the disease. This study confirms that combining MRI pattern recognition to define small, homogeneous patient groups with WES is a powerful approach for providing a fast diagnosis in patients with an unclassified genetic encephalopathy.

• MeSH
• geny recesivní genetika   MeSH
• kojenec MeSH
• lidé MeSH
• mutace genetika   MeSH
• nemoci mozku diagnóza   genetika   MeSH
• předškolní dítě MeSH
• pyrofosfatasy chemie   genetika   MeSH
• sekundární struktura proteinů MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH