[Perinatal lethal Gaucher disease. Case report]. / Perinatal'nyi letal'nyi variant bolezni Goshe. Opisanie nablyudeniya.

The paper describes a case of a perinatal lethal Gaucher disease in a 29-week-old fetus with non-immune hydrops, facial dysmorphia, hepatosplenomegaly, and hypoplasia of cerebellum and pons. Gaucher cells were found in the lymph nodes, spleen, lungs, thymus, cerebellum, and bone marrow. No storage cells have been detected in the placenta. There was a significant placental weight increase due to swelling. The diagnosis of Gaucher disease was confirmed by biochemical analysis (deficiency of glucocerebrosidase activity and sharply increased hexanoylsphingosine concentration) and molecular genetic techniques (the presence of two mutations of the GBA gene). Our observation shows that characteristic histologic signs of disease can be detected at early stages of development.

Mucopolysaccharidosis Type I in the Russian Federation and Other Republics of the Former Soviet Union: Molecular Genetic Analysis and Epidemiology.

Mutations in the IDUA gene cause deficiency of the lysosomal enzyme alpha-l-iduronidase (IDUA), which leads to a rare disease known as mucopolysaccharidosis type I. More than 300 pathogenic variants of the IDUA gene have been reported to date, but not much is known about the distribution of mutations in different populations and ethnic groups due to the low prevalence of the disease. This article presents the results of a molecular genetic study of 206 patients with mucopolysaccharidosis type I (MPS I) from the Russian Federation (RF) and other republics of the former Soviet Union. Among them, there were 173 Russian (Slavic) patients, 9 Tatars, and 24 patients of different nationalities from other republics of the former Soviet Union. Seventy-three different pathogenic variants in the IDUA gene were identified. The common variant NM_000203.5:c.208C>T was the most prevalent mutant allele among Russian and Tatar patients. The common variant NM_000203.5:c.1205G>A accounted for only 5.8% mutant alleles in Russian patients. Both mutations were very rare or absent in patients from other populations. The pathogenic variant NM_000203.5:c.187C>T was the major allele in patients of Turkic origin (Altaian, Uzbeks, and Kyrgyz). Specific own pathogenic alleles in the IDUA gene were identified in each of these ethnic groups. The identified features are important for understanding the molecular origin of the disease, predicting the risk of its development and creating optimal diagnostic and treatment tools for specific regions and ethnic groups.

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.

[High resolution respirometry in diagnostic of mitochondrial disorders caused by mitochondrial complex I deficiency]. / Respirometriia vysokogo razresheniia v diagnostike mitokhondrial'nykh zabolevanii s narusheniem raboty I kompleksa dykhatel'noi tsepi mitokhondrii.

Complex I (CI) deficiency is one of the most common defects in the OXPHOS system; it represents more than 30% cases of mitochondrial diseases. The group is characterized by clinical and genetic heterogeneity and comprise several nosological forms. The most prevalent phenotypes for CI are LHON and Leigh syndrome. In this study we have analyzed skin fibroblasts from 11 patients with mutations in mtDNA, which cause LHON or Leigh-like phenotypes: m.11778 G>A (n=3), m.3460 A>G (n=2), m.3635 G>A (n=1), m.3308 T>G (n=2), m.3472 T>C (n=1) and 2 patients with earlier unknown substitutions m.3945 C>A and m.14441T>C. High-resolution respirometry (HRR) on the Oxygraph-2k instrument ("Oroboros corp.", Austria) was performed for complex analysis of the mitochondrial respiratory function in intact and permeabilized fibroblasts of patients and healthy controls. Flux control rations in intact cells R/E, (R-L)/E (p<0.05) were raised compared to the control. Rates of R, E, L normalized on the CS were statistically varied between patients and controls. In permeabilized fibroblasts we observed differences in CII/E, Rot/E, R/CII, CI/CII (p<0.05) between groups. These data highlight the dysfunction of the OXPHOS system and particularly CI. Increased citrate synthase level and decreased CI/CII ratio indicate compensatory metabolic response to respiratory chain dysfunction. Our results show applicability of HRR in revealing the biochemical abnormalities of complex I in fibroblasts of patients with LHON and Leigh-like syndrome. We also suggest HRR to be a useful method for inspection of other mutations causing complex I deficiency.

[L-2-hydroxyglutaric aciduria caused by a new mutation in the L2HGDH gene]. / Sluchai L-2-gidroksiglutarovoi atsidurii, obuslovlennoi novoi mutatsiei v gene L2HGDH.

The authors present a case-report of 13 year-old girl with L-2-hydroxyglutaric aciduria [MIM#236792], a rare autosomal/recessive metabolic disorder caused by mutations in the L-encoding 2-hydroxyglutarate dehydrogenase (L2HGDH, 14q21.3). Clinical signs of the disease are presented by predominantly neurological symptoms (epilepsy, cerebellar ataxia, cognitive impairment). The distinctive feature is the specific multifocal lesion of the white matter detected on MRI. The characteristic neuroimaging picture and positive results of biochemical and molecular genetic diagnosis were identified.

[Mutation del 1,02kb in the CLN3 gene and extrapyramidal syndrome]. / Mutatsiya del 1,02 kb v gene CLN3 i sindrom ekstrapiramidnykh rasstroistv.

Mutations in the GBA and SMPD1 genes, which lead to the development of lysosomal storage diseases, are high risk factors for Parkinson's disease and dementia with Lewy bodies. We screened the mutations in the GALC and CLN3 genes in patients with Parkinson's disease and control subjects. A heterozygous CLN3 mutation (del 1.02 kb) carrier with clinical features of the unusual extrapyramidal syndrome was identified. A role of CLN3 mutations in the development of neurodegenerative disorders is discussed.

Increased plasma oligomeric alpha-synuclein in patients with lysosomal storage diseases.

A link between lysosomal storage diseases (LSDs) and neurodegenerative disorders associated with accumulation of presynaptic protein alpha-synuclein has been shown. Particularly, Gaucher disease (GD) patients with a deficiency of the lysosomal enzyme glucocerebrosidase (GBA) and carriers of GBA mutations are at increased risk of Parkinson's disease (PD). It remains unclear whether this link is due to increased alpha-synuclein oligomerization. Here we show that level of oligomeric alpha-synuclein form, associated with PD development, is increased in plasma of GD patients (n=41, median=22.9pg/mL, range1.57-444.58pg/mL; controls (n=40, median=6.02pg/mL, range 1.05-103.14pg/mL, p<0.0001). This difference is absent in GD patients receiving enzyme replacement therapy (ERT) for more than 5 years. Moreover, the levels of alpha-synuclein oligomers in plasma are also higher in patients with other LSDs (Niemann-Pick type C, Krabbe disease, Wolman disease) compared to the median value in controls. Therefore, we suggest that mutations in the GBA gene and at least in several other LSDs genes may be associated with an increase in oligomeric alpha-synuclein in plasma. ERT applied for recovering of GBA functions in GD treatment might decrease formation of plasma oligomeric alpha-synuclein.

[A new form of hereditary neurodegeneration with brain iron accumulation: clinical and molecular-genetic characteristics].

Neurodegeneration with brain iron accumulation, type 4 (NBIA4, or MPAN) is an autosomal recessive disease produced by С19org12 mutations. NBIA group includes also most common NBIA1 or PKAN (formerly Hallervorden-Spatz disease) NBIA2 or PLAN, and few others. Common NBIA features are onset in childhood or adolescence, progressive movement disorders (spasticity, dystonia, parkinsonism), dysarthria, optic atrophy, cognitive and neuropsychiatric disorders, and MRI picture of iron accumulation in globus pallidum and substantia nigra. Though only recently recognized, NBIA4 was reported in many populations and seems to be not rare. We diagnosed NBIA4 in three non-consanguineous Russian families. Case 1, 19-year-old female, had slowly progressing leg spasticity since 12 yrs, moderate dystonia in neck, hands and feet since 17-18 yrs, optic atrophy detected in 18 yrs and mild cognitive impairment; MRI was normal in 14 yrs, but in 17 yrs showed typical NBIA signs. Case 2, 16-year-old male, had slowly progressing spasticity, dystonia, ataxia and mild dementia since 11-12 yrs; MRI was normal up to 16 yrs when NBIA signs appeared; optic atrophy was seen at the same age. In both patients homozygosity for C19orf12 mutation с.204_214del11 (Gly69ArgfsX10) was detected. The mutation is most common in Polish and other East European populations. Case 3 is atypical in several aspects. The patient is 35-year-old female with Usher syndrome, autosomal recessive disease including congenital sensorineural deafness and retinitis pigmentosa; her junior sister is also affected. MRI was performed because of headaches and unexpectedly detected NBIA picture (MRI in the sister could not be performed due to technical contra-indications). No NBIA symptoms were seen in 35 and in 36.5 yrs. Heterozygosity for the same C19orf2 mutation Gly69ArgfsX10 was detected in the patient, but not in the sister; allelic mutation was not found by now. We consider the case as co-existence of two independent disorders: typical Usher syndrome in two sisters and atypical, subclinical NBIA4 in senior one.