[Gerstmann-Sträussler disease: a familial case with common PRNP mutation and atypical features]. / Bolezn' Gerstmana­Shtrosslera: semeinyi sluchai s chastoi mutatsiei gena PRNP i atipichnymi proyavleniyami.

Gerstmann-Sträussler disease (GSD) is a very rare autosomal dominant late-onset neurodegenerative disorder related to prion protein gene PRNP. Mutation p.Pro102Leu produces about 80% of cases, which are often named GSD-102. DNA testing provides exact diagnosis. In the presented Russian family there were 3 patients: a female index case, age 32 years, her brother, age 37 years (age of onset in both is 27 years) and their deceased father (onset in 35 years, death in 44 years). GSD was not suspected until whole exome sequencing in the female detected PRNP mutation p.Pro102Leu confirmed in her and in the brother by Sanger sequencing. Atypical features of the case are: early onset in siblings, absence of mental and behavioral problems in the female and in the father and mild disturbances in the brother; epilepsy in the brother; atypical onset with transient signs in the brother. Other intrafamilial differences are prevailing spastic paraparesis in the female in contrast to predominant ataxia in the brother and dysarthria absence in the female. The case illustrates GSD-102 variability, complicating clinical diagnostics.

[Autosomal dominant spastic paraplegias]. / Autosomno-dominantnye spasticheskie paraplegii.

OBJECTIVE: To estimate the proportion and spectrum of infrequent autosomal dominant spastic paraplegias in a group of families with DNA-confirmed diagnosis and to investigate their molecular and clinical characteristics. MATERIAL AND METHODS: Ten families with 6 AD-SPG: SPG6 (n=1), SPG8 (n=2), SPG9A (n=1), SPG12 (n=1), SPG17 (n=3), SPG31 (n=2) were studied using clinical, genealogical, molecular-genetic (massive parallel sequencing, spastic paraplegia panel, whole-exome sequencing, multiplex ligation-dependent amplification, Sanger sequencing) and bioinformatic methods. RESULTS AND CONCLUSION: Nine heterozygous mutations were detected in 6 genes, including the common de novo mutation p.Gly106Arg in NIPA1 (SPG6), the earlier reported mutation p.Val626Phe in WASHC5 (SPG8) in isolated case and the novel p.Val695Ala in WASHC5 (SPG8) in a family with 4 patients, the novel mutation p.Thr301Arg in RTN2 (SPG12) in a family with 2 patients, the novel mutation c.105+4A>G in REEP1 (SPG31) in a family with 4 patients and the reported earlier p.Lys101Lys in REEP1 (SPG31) in a family with 3 patients, the known de novo mutation p.Arg252Gln in ALDH18A1 (SPG9A) in two monozygous twins; the common mutation p.Ser90Leu in BSCL2 (SPG17) in a family with 3 patients and in isolated case, reported mutation p.Leu363Pro in a family with 2 patients. SPG6, SPG8, SPG12 and SPG31 presented 'pure' phenotypes, SPG31 had most benign course. Age of onset varied in SPG31 family and was atypically early in SPG6 case. Patients with SPG9A and SPG17 had 'complicated' paraplegias; amyotrophy of hands typical for SPG17 was absent in a child and in an adolescent from 2 families, but may develop later.

Novel intronic variant in PALB2 gene and effective prevention of Fanconi anemia in family.

Despite the acceptance of NextGen sequencing as a diagnostic modality suitable for probands and carriers of Mendelian diseases, its efficiency in identifying causal mutations is limited by both technical aspects of variant call algorithms and by imperfect, consensus-based criteria for assessing the pathogenicity of the findings. Here we describe the medical history of the family with a child born with Fanconi anemia. In this case, typical diagnostic routines were complicated by unusual combination of mutations. PALB2 variant NM_024675.3:c.172_175delTTGT (p.Gln60Argfs) in maternal sample, previously classified as a definitely pathogenic frameshift mutation, was in compound heterozygous state with PALB2 NM_024675.3:c.3114-16_3114-11del (p.Asn1039Glyfs*7), which led to validated PALB2 exon 11 skipping event in paternal locus. Findings enabled the development of the PGТ and successful selection of two mutation-free embryos. We show that even in absence of definitive exome findings, clinician-guided research inquiries into the structure and function of the suspected loci allow definitive diagnosis. Described case provides an example of a crucial input of an investigational workflow in genetic prognosis and successful PGT.

[Ataxia-telangiectasia with rare phenotype and unusual pedigree]. / Ataksiia-teleangiéktaziia s redkim fenotipom i neobychnoi rodoslovnoi.

The authors present an unique familial case of ataxia-telangiectasia (AT) mimicking autosomal dominant inheritance with different phenotypes in a 3-year-old boy (ataxia and moderate dyskinesia since 1.5 years) and his 31-year-old mother (mild dystonia, predominantly torticollis, since 10 years). Exome sequencing of the boy detected two heterozygous ATM mutations c.1564_1565delGA (p.Glu522fs) and c.6154G>A (p.Glu2052Lys) reported earlier. Sanger sequencing found both mutations in the child, the father was heterozygous for c.1564_1565delGA, the mother for 6154G>A earlier reported in the rare A-T phenotype of 'pure' local dystonia. Exome sequencing of the mother, who considered herself healthy, detected the allelic ATM mutation c.7630-2A>C in intron 51.

De novo truncating variants in the intronless IRF2BPL are responsible for developmental epileptic encephalopathy.

PURPOSE: Developmental and epileptic encephalopathies (DEEs) are severe clinical conditions characterized by stagnation or decline of cognitive and behavioral abilities preceded, accompanied or followed by seizures. Because DEEs are clinically and genetically heterogeneous, next-generation sequencing, especially exome sequencing (ES), is becoming a first-tier strategy to identify the molecular etiologies of these disorders. METHODS: We combined ES analysis and international data sharing. RESULTS: We identified 11 unrelated individuals with DEE and de novo heterozygous truncating variants in the interferon regulatory factor 2-binding protein-like gene (IRF2BPL). The 11 individuals allowed for delineation of a consistent neurodevelopmental disorder characterized by mostly normal initial psychomotor development followed by severe global neurological regression and epilepsy with nonspecific electroencephalogram (EEG) abnormalities and variable central nervous system (CNS) anomalies. IRF2BPL, also known as enhanced at puberty protein 1 (EAP1), encodes a transcriptional regulator containing a C-terminal RING-finger domain common to E3 ubiquitin ligases. This domain is required for its repressive and transactivating transcriptional properties. The variants identified are expected to encode a protein lacking the C-terminal RING-finger domain. CONCLUSIONS: These data support the causative role of truncating IRF2BPL variants in pediatric neurodegeneration and expand the spectrum of transcriptional regulators identified as molecular factors implicated in genetic developmental and epileptic encephalopathies.

[New allelic variants of non-syndromic mental retardation of type 20 caused by mutations in the MEF2C gene]. / Novye allel'nye varianty nesindromal'noi umstvennoi otstalosti 20-go tipa, obuslovlennoi mutatsiiami v gene.

AIM: To determine clinical and genetic characteristics of patients with non-syndromic mental retardation (NMR), type 20 with autosomal dominant type of inheritance (OMIM: 613443). MATERIAL AND METHODS: Fourteen patients were studied including four patients with mutations in the MEF2C gene revealed by exome sequencing. Three of the four mutations in the gene were found for the first time. RESULTS: Based on a comparative analysis of the clinical manifestations of 4 observed patients and 9 patients with type 20 NMR described in the literature, the authors determined common clinical characteristics of this syndrome. In most cases with delayed psycho-speech development and convulsive syndrome, the patients were expected to have various variants of early epileptic encephalopathies, in which presence of convulsive paroxysms leads to intellectual deficit, while in the case of NMR, the delay in development can be noted long before the onset of seizures. CONCLUSION: Exome sequencing is the most effective method of NMR diagnosis.

[Ataxia with oculomotor apraxia type 4 detected by next-generation sequencing]. / Ataksiia s okulomotornoi apraksiei 4-go tipa, diagnostirovannaia metodom panel'nogo ékzomnogo sekvenirovaniia.

Ataxias with oculomotor apraxia (AOA) belong to autosomal recessive ataxias. Their common feature is oculomotor apraxia: inability to coordinate eye movements not due to muscle weakness. Next-generation sequencing (NGS) gives unique opportunities of rare disorders diagnostics and discovering of new forms, including AOA. In 2015, AOA type 4 produced by PNKP mutations was delineated in a group of Portuguese patients. We diagnosed AOA4 in a 9-year-old boy from Byelorussian family. He presented with ataxia since 2 years and deterioration in 8 years, oculomotor apraxia, dystonic hyperkinesia, dysarthria, polyneuropathy, borderline/mildly impaired intelligence, cerebellar atrophy on MRI and moderate hypercholesterolemia. Panel NGS detected two PNKP mutations: c.1123G>T (p.Gly375Trp) common in Portuguese patients, and novel c.1270_1283dupACAAACCCAGACGC (p.Ala429fs). This is one of a few world AOA4 cases and first non-Portuguese case with 'Portuguese' common mutation. The case illustrates NGS diagnostic value, particularly in rare heterogeneous disorders like AOA.

[BRAF-positive paucicellular variant of anaplastic carcinoma in the presence of tall cell variant papillary thyroid cancer]. / BRAF-pozitivnyi malokletochnyi variant anaplasticheskoi kartsinomy na fone papilliarnogo raka shchitovidnoi zhelezy iz vysokikh kletok.

To paper describes a case of paucicellular anaplastic cancer in the presence of tall cell variant papillary thyroid carcinoma. Microscopic examination showed that the differentiated component of the tumor was composed of papillary structures with tall cells, the height of which exceeded 3-4 times the width. Its anaplastic component consisted of fibrous tissue with occasional spindle-shaped cells and focal lymphocytic infiltration to the extent of 70%. The spindle-shaped cells expressed cytokeratins, ß-catenin, p53, and vimentin. The tumor cells and lymphocytes showed an association with Epstein-Barr virus. Molecular genetic study of the tumor revealed the following mutations: BRAF p.Val600Glu (p.V600e was), HRAS p.His27His (p.H27H), PIK3CA p.Glu545Lys (p.E545K), TP53 p.Arg248Gln (p.R248Q).

[CAPS markers for the identification of garden pea (Pisum sativum L.) cultivars].

The CAPS (PCR-PDRF) method was used to analyze polymorphism in sequences of unique genes among specimens of 24 pea lines and cultivars. Analysis of each employed molecular-genetic marker was found to reveal three to seven polymorphic sequence variants. Analysis with the use of five selected markers allows the unambiguous identification of any of examined specimens. Thus, the possibility of using CAPS markers for identification and classification of garden pea cultivars has been shown. Possible prospects for this approach and the ways of its further implementation are considered.

[Identification and mapping of polymorphic RAPD markers of pea (Pisum sativum L.) genome].

Various pea cultivars, lines, and mutants were studied by the RAPD method. Polymorphic fragments characteristic of certain pea genotypes and which can be used for identifying genotypes were detected. Inheritance of some polymorphic RAPD fragments was studied. Mendelian inheritance of these fragments was shown. By analyzing the data obtained in studies of RAPD polymorphism, genetic distances between different pea cultivars, lines, and mutants were calculated and a genealogic dendogram showing a varying extent of differences between RAPD patterns was constructed. Ten new RAPD markers linked to various pea genes were detected. Genetic distances between RAPD markers and genes to which they are linked were calculated, and the respective disposition of RAPD markers on chromosomes was established.

[Studying plant genome variation using molecular markers].

The authors' studies on the organization and variation of plant genome with the use of molecular markers are briefly reviewed with special emphasis on random amplified polymorphic DNA (RAPD), inter simple sequence repeat (ISSR), sequence characterized amplified region (SCAR), and cleaved amplified polymorphic sequence (CAPS) markers detected with the use of polymerase chain reaction (PCR). These markers have been demonstrated to be promising for identifying cultivars and determining the purity of genetic strains of pea. Genetic relationships between strains, cultivars, and mutants of pea have been studied. The role of molecular markers in molecular genetic mapping and localizing the genes of commercially important characters of pea has been shown. The possibility of the use of molecular markers for studying somaclonal variation and detecting mutagenic factors in plants during long-term spaceflights is considered. The prospects of using DNA markers for understanding the organization and variability of higher plant genomes are discussed.

Studying plant genome variation using molecular markers.

The authors' studies on the organization and variation of plant genome with the use of molecular markers are briefly reviewed with special emphasis on random amplified polymorphic DNA (RAPD), inter simple sequence repeat (ISSR), sequence characterized amplified region (SCAR), and cleaved amplified polymorphic sequence (CAPS) markers detected with the use of polymerase chain reaction (PCR). These markers have been demonstrated to be promising for identifying cultivars and determining the purity of genetic strains of pea. Genetic relationships between strains, cultivars, and mutants of pea have been studied. The role of molecular markers in molecular genetic mapping and localizing the genes of commercially important characters of pea has been shown. The possibility of the use of molecular markers for studying somaclonal variation and detecting mutagenic factors in plants during long-term spaceflights is considered. The prospects of using DNA markers for understanding the organization and variability of higher plant genomes are discussed.

[Identification and mapping of chi115 gene and DNA markers linked to it in pea (Pisum sativum L.)]. / Identifikatsii i lokalizatsii gena chi115 i stseplennykh stseplennykh s nim DNK-markerov u gorokha posevnogo (Pisum sativum L.)

Chlorophyll mutant Chi115 was induced by ethylmethane sulfonate (EMS) treatment of seeds of genotype Torsdag in Moscow State University and is characterized by lighter plant color. The monogenic nature of the mutant was determined by analyzing the F2 population from a cross between two P. sativum genotypes, WL1238 and Chi115. To establish a local map around the chi115 gene, the RAPD and ISSR techniques were used with 45 RAPD and 10 ISSR primers in combination with bulked segregant analysis (BSA). Linkage of 12 RAPDs and 2 ISSRs to the chi115 locus was observed in analysis of F2 single plants. Two RAPD markers that were closely associated with the chi115 gene were converted into the sequence characterized amplified region (SCAR) markers. By lowering the LOD score to 2, the linkage group containing the chi115 gene could be linked to the b gene (color of the flower) on linkage group III. Nevertheless, to prove the result obtained, three CAPS markers Sodmt, TubA1, and Rb were chosen on linkage group III. The results of linkage analysis showed that these CAPS markers were located within the linkage group including the chi115 gene.