Ornithine transcarbamylase (OTC) deficiency is an X-linked disorder that causes recurrent and life-threatening episodes of hyperammonemia. The clinical picture in heterozygous females is highly diverse and derives from the genotype and the degree of inactivation of the mutated X chromosome in hepatocytes. Here, we describe molecular genetic, biochemical, and histopathological findings in the livers explanted from two female patients with late-onset OTC deficiency. Analysis of X-inactivation ratios by DNA methylation-based assays showed remarkable intra-organ variation ranging from 46:54 to 82:18 (average 70:30, n = 37), in favor of the active X chromosome carrying the mutation c.583G>C (p.G195R), in the first patient and from 75:25 to 90:10 (average 82:18, n = 20) in favor of the active X chromosome carrying the splicing mutation c.663+1G>A in the second patient. The X-inactivation ratios in liver samples correlated highly with the proportions of OTC-positive hepatocytes calculated from high-resolution image analyses of the immunohistochemically detected OTC in frozen sections that was performed on total area > 5 cm2. X-inactivation ratios in blood in both female patients corresponded to the lower limit of the liver values. Our data indicate that the proportion of about 20-30% of hepatocytes expressing the functional OTC protein is not sufficient to maintain metabolic stability. X-inactivation ratios assessed in liver biopsies taken from heterozygous females with X-linked disorders should not be considered representative of the whole liver.

• Klíčová slova
• Glutamine synthetase, Glycogen storage, Liver, Liver zonation, Ornithine transcarbamylase, X chromosome inactivation,
• MeSH
• biopsie MeSH
• genotyp MeSH
• glutaminsynthetasa genetika   metabolismus   MeSH
• heterozygot MeSH
• inaktivace chromozomu X * MeSH
• játra enzymologie   MeSH
• lidé MeSH
• lidské chromozomy X genetika   MeSH
• nemoc z nedostatku ornithinkarbamoyltransferázy genetika   MeSH
• ornithinkarbamoyltransferasa genetika   metabolismus   MeSH
• pohlavní dimorfismus MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glutaminsynthetasa MeSH
• ornithinkarbamoyltransferasa MeSH

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder characterized by developmental regression with loss of motor, communication and social skills, onset of stereotypic hand movements and often seizures. RTT is primarily caused by de novo mutations in the methyl-CpG-binding protein 2 gene (MECP2). We established a high-resolution melting (HRM) technique for mutation scanning of the MECP2 gene and performed analyses in Czech patients with RTT, autism spectrum conditions and intellectual disability with Rett-like features. In the cases with confirmed MECP2 mutations, we determined X-chromosome inactivation (XCI), examined the relationships between genotype and clinical severity and evaluated the modifying influence of XCI. Our results demonstrate that HRM analysis is a reliable method for the detection of point mutations, small deletions and duplications in the MECP2 gene. We identified 29 pathogenic mutations in 75 girls, including four novel mutations: c.155_1189del1035;909_932inv;insC, c.573delC, c.857_858dupAA and c.1163_1200del38. Skewed XCI (ratio >75%) was found in 19.3% of the girls, but no gross divergence in clinical severity was observed. Our findings confirm a high mutation frequency in classic RTT (92%) and a correlation between the MECP2 mutation type and clinical severity. We also demonstrate limitations of XCI in explaining all of the phenotypic differences in RTT.

• MeSH
• alely MeSH
• dítě MeSH
• exony MeSH
• fenotyp * MeSH
• genetická predispozice k nemoci MeSH
• genetické asociační studie * MeSH
• genotyp * MeSH
• inaktivace chromozomu X MeSH
• jednonukleotidový polymorfismus MeSH
• lidé MeSH
• mladiství MeSH
• mutace * MeSH
• mutační analýza DNA MeSH
• předškolní dítě MeSH
• protein 2 vázající methyl-CpG genetika   MeSH
• Rettův syndrom diagnóza   genetika   MeSH
• techniky amplifikace nukleových kyselin MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• protein 2 vázající methyl-CpG MeSH

We have identified 21 different alpha-galactosidase A gene (GLA) mutations in 22 unrelated Czech and Slovak families with Fabry disease. Eleven of these mutations were novel (point mutations D93N, A135V, D155H, G171R, Q280K, G360S, Q330X, splicing errors c.194ins14, c.801ins36 and deletions c.674_732del59, g.3405_6021del2617). Genotyping of family members for family-specific mutations revealed 55 heterozygotes that manifested clinical symptoms of different severity. To examine the contribution of X-inactivation skewing to disease manifestation in Fabry heterozygotes, we have adopted the Mainz severity scoring scheme and compared the score values with the X-inactivation status in 39 carriers in an age-dependent manner. The age-score trendline of Fabry females who had a predominantly inactivated X-chromosome bearing a wild-type GLA allele (10 of 38 females) was markedly steeper than in the rest of the cohort. One female carrier with an inactivated mutated allele had a low score value when compared to the other heterozygotes of the same age. These data suggest that X-inactivation is indeed a major factor determining the severity of clinical involvement in Fabry heterozygotes. There was a statistically significant difference between the severity score values of heterozygotes with random and non-random X-chromosome inactivation at the 5% level of significance. Further studies will show if the degree of the wildtype allele inactivation will be useful as a predictive marker of severity of phenotype in Fabry heterozygotes. Although the correlation between X-inactivation skewing and presentation of the disease in Fabry heterozygotes has previously been suggested in the literature, this report is among the first attempts to examine this relationship systematically.

• MeSH
• alfa-galaktosidasa genetika   MeSH
• bodová mutace MeSH
• dítě MeSH
• dospělí MeSH
• Fabryho nemoc epidemiologie   genetika   MeSH
• genetické nemoci vázané na chromozom X * MeSH
• heterozygot MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• stupeň závažnosti nemoci MeSH
• umlčování genů * MeSH
• věkové faktory MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Slovenská republika epidemiologie   MeSH
• Názvy látek
• alfa-galaktosidasa MeSH

Hemosiderotic fibrohistiocytic lipomatous lesion (HFLL) is a recently proposed lipomatous entity. HFLL was originally suggested to be a benign reactive lesion arising due to an antecedent trauma. We report two patients with HFLL who also suffered from chronic vein insufficiency due to varicose involving deep veins of the low limbs. Both patients were middle-aged women with solitary, poorly circumscribed subcutaneous lesions on the lower extremities. Histopathological examination revealed typical features of HFLL. We think that the consistent clinical features such as advanced age, female sex predilection, and specific location along with distinctive histopathological features allow the suggestion that impaired blood circulation, to wit, venous stasis is involved in the pathogenesis of HFLL. We hypothesize that the proliferation of spindled fibroblastic and myofibroblastic cells and capillaries, erythrocyte extravasation, and hemosiderin deposition with lipomatous tissue of HFLL may simply represent an exaggerated tissue response to venous stasis in which elevated venous and capillary pressures, oxygen saturation, and edema stimulate the proliferation of the above mentioned elements and lead to erythrocyte extravasation. A similar histopathological pattern is seen in acroangiodermatitis of Mali and vascular transformation of lymph node sinuses, and these conditions are also associated with impaired blood circulation.

• MeSH
• hemosiderin analýza   MeSH
• hemosideróza komplikace   patologie   chirurgie   MeSH
• histiocytóza komplikace   patologie   chirurgie   MeSH
• imunohistochemie MeSH
• lidé středního věku MeSH
• lidé MeSH
• lipom komplikace   patologie   chirurgie   MeSH
• nádorové biomarkery analýza   MeSH
• nádory měkkých tkání komplikace   patologie   chirurgie   MeSH
• tuková tkáň chemie   patologie   MeSH
• varixy komplikace   patologie   chirurgie   MeSH
• výsledek terapie MeSH
• žilní insuficience komplikace   patologie   chirurgie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• hemosiderin MeSH
• nádorové biomarkery MeSH