Generation of two iPSC lines from patient with Mucopolysaccharidosis IV B type and autosomal recessive non-syndromic hearing loss 12.

We generated two human induced pluripotency stem cell (hiPSC) lines, RCMGi011-A and 11-B, from skin fibroblast from patient with Mucopolysaccharidosis IV B type and autosomal recessive non-syndromic hearing loss 12 using non-integrating, viral CytoTune™-iPS 2.0 Sendai Reprogramming Kit. We verified variant c.808 T > G and insertion in GLB1 gene, as well as two mutations, c.6992 T > C and c.805C > T, in CDH23 gene which lead to autosomal recessive hearing loss type 12. We have demonstrated normal karyotype of hiPSCs and capacity for cell differentiation into three germ layers.

Mitochondrial DNA maintenance disorders in 102 patients from different parts of Russia: Mutational spectrum and phenotypes.

Currently, pathogenic variants in more than 25 nuclear genes, involved in mtDNA maintenance, are associated with human disorders. mtDNA maintenance disorders manifest with a wide range of phenotypes, from severe infantile-onset forms of myocerebrohepatopathy to late-onset forms of myopathies, chronic progressive external ophthalmoplegia, and parkinsonism. This study represents the results of molecular genetic analysis and phenotypes of 102 probands with mtDNA maintenance disorders. So far, this is the largest Russian cohort for this group of diseases. Mutations were identified in 10 mtDNA maintenance genes: POLG (n = 59), DGUOK (n = 14), TWNK (n = 14), TK2 (n = 8), MPV17 (n = 2), OPA3 (n = 1), FBXL4 (n = 1), RRM2B (n = 1), SUCLG1 (n = 1) and TYMP (n = 1). We review a mutation spectrum for the DGUOK and TWNK genes, that can be specific for the Russian population. In 34 patients we measured the blood mtDNA copy number and showed its significant reduction. Novel variants were found in 41 cases, which significantly expands the mutational landscape of mtDNA maintenance disorders.

α-Galactosidase A/lysoGb3 ratio as a potential marker for Fabry disease in females.

Fabry disease (FD [MIM:301500]) is an X-linked lysosomal storage disorder caused by mutations in the GLA gene. Deficient activity of its product, lysosomal enzyme α-galactosidase A (α-Gal A), leads to excessive accumulation of glycosphingolipids in cells of multiple organs. The establishing of the diagnosis is challenge in female patients because of milder clinical manifestation and normal α-Gal A activity. The globotriaosylsphingosine (lysoGb3) is described as a more sensitive diagnostic biomarker for females with pathogenic mutation in the GLA gene. Thus, the aim of this study is to improve the biochemical diagnostic efficiency for FD in females. Here we report the α-Gal A/lysoGb3 ratio as the novel biochemical criteria for diagnosis of female patients with FD, using dried blood spots (DBS) as test samples. It showed 100% sensitivity in distinguishing our group of 35 female patients from control (n = 140). Whereas measurement of α-Gal A and lysoGb3 alone showed 8.6% and 74.4% respectively. A new approach of using the ratio of α-Gal A activity to lysoGb3 concentration in DBS may provide a more accurate screening tool for identification of FD females.

The novel synonymous variant in LIPA gene affects splicing and causes lysosomal acid lipase deficiency.

Lysosomal acid lipase deficiency (LALD; MIM#278000) is a continuum of autosomal recessive diseases caused by defects in the gene LIPA and historically divided into two phenotypes: severe infantile-onset form called Wolman disease (WD) and childhood/adult-onset form known as cholesteryl ester storage disease (CESD). We report a novel synonymous homozygous variant c.600G > A in LIPA of a patient with LALD. Functional analysis of the patient cDNA and minigene assay revealed this variant as the cause of exonic cryptic splice site activation and 63 b.p. deletion in exon 6. To investigate the impact of this in-frame deletion on protein function, we performed 3D modeling of the human lysosomal acid lipase and showed the alteration of highly conservative region in close proximity to protein active site, which may completely eliminate the enzymatic activity. Using transcript specific real-time quantitative PCR method, we evaluated the relative ratio of the patient's wild type transcript isoform which is significantly reduced and correlates with severe childhood-onset variant of LALD.

The Unique Spectrum of Mutations in Patients with Hereditary Tyrosinemia Type 1 in Different Regions of the Russian Federation.

BACKGROUND: Hereditary tyrosinemia (HT1) is an autosomal recessive disorder characterized by impaired tyrosine catabolism because of fumarylacetoacetate hydrolase deficiency. HT1 is caused by homozygous or compound heterozygous mutations in the FAH gene. The HT1 frequency worldwide is 1:100,000-1:120,000 live births. The frequency of HT1 in the Russian Federation is unknown. AIM: To estimate the spectrum of mutations in HT1 in several ethnic groups of the Russian Federation. MATERIALS AND METHODS: From 2004 to 2017, 43 patients were diagnosed with HT1. The analysis of amino acids and succinylacetone was performed using NeoGram Amino Acids and Acylcarnitines Tandem Mass Spectrometry Kit and a Sciex QTrap 3200 quadrupole tandem mass spectrometer. Bi-directional DNA sequence analysis was performed on PCR products using an ABI Prism 3500. RESULTS: In the Russian Federation, the most common mutation associated with HT1 (32.5% of all mutant alleles) is c.1025C>T (p.Pro342Leu), which is typical for the Chechen ethnic group. Patients of the Yakut, the Buryat, and the Nenets origins had a homozygous mutation c.1090G>C (p.Glu364Gln). High frequency of these ethnicity-specific mutations is most likely due to the founder effect. In patients from Central Russia, the splicing site mutations c.554-1G>T and c.1062+5G>A were the most prevalent, which is similar to the data obtained in the Eastern and Central Europe countries. CONCLUSION: There are ethnic specificities in the spectrum of mutations in the FAH gene in HT1. The Chechen Republic has one of the highest prevalence of HT1 in the world.