Clinical Importance of aCGH in Genetic Counselling of Children with Psychomotor Retardation.

Introduction: The X and Y chromosomes are responsible for the determination and differentiation of the gonads, and their numerical and structural abnormalities may cause the abnormal development of secondary sex characteristics. The presence of abnormalities concerning X chromosome can also contribute to many genetically heterogeneous diseases associated with cognitive impairment and intellectual disability. Purpose: This study shows the effect of aberrations of the maternal X chromosome on the abnormal development of the child. Patients and Methods: Ten women aged 26 to 40 years were consulted in genetic counselling clinic and subsequently subjected to cytogenetic and molecular tests due to abnormal psychomotor development of their children, in whom structural aberrations of the X chromosome had been detected. Results: Two women were diagnosed with changes in karyotype: 46,X,der(X)t(X;Y)(p22.3;q11.2) in one and 46,X,inv(X)(p21.2q13). Five women were diagnosed with microduplications in the short arm of the X chromosome; dupXp22.31 in one, and in four women dupXp22.33. The remaining three women were diagnosed with duplication in the long arm of the X chromosome; dupXq25 in one and dupXq26.3 in two women. Conclusion: Genetic analysis of the X chromosome, based on cytogenetic and molecular methods of the highest available resolution, is extremely important in women with reproductive failure. These methods allow establishing accurately the breakpoints and rearrangements in chromosomes, and assessment of the copy number variation (CNV) can explain phenotypic variability with apparently similar aberrations. A more precise characterization of the alterations is necessary for the correct genetic diagnosis, as well as determination of the carrier status and genetic risk in family members.

Evaluation of the frequency of ADIPOQ c.45 T>G and ADIPOQ c.276 G>T polymorphisms in adiponectin coding gene in girls with anorexia nervosa.

INTRODUCTION: Anorexia nervosa (AN) is a serious chronic psychosomatic disorder, the essence of which are attempts by the sufferer to obtain a slim silhouette by deliberate weight loss (restrictive diet, strenuous physical exercise, provoking vomiting). The aetiology of this disorder is multifactorial. Genetic factors that influence the predisposition to AN have been sought. A broad meta-analysis points to a strong genetic correlation between AN and insulin resistance. Adiponectin (ADIPO) increases insulin sensitivity. In our pilot study we demonstrated that the TT genotype in locus ADIPOQ c.276 G>T of the ADIPO gene and a higher concentration of ADIPO in blood serum occurred significantly more frequently in 68 girls suffering from AN than in 38 healthy girls. The objective of this study was to evaluate the frequency of the occurrence of ADIPOQ c.45 T>G and ADIPOQ c.276 G>T in the ADIPO gene in a larger cohort of girls with AN and healthy girls, as well as an analysis of correlations between variants of the aforementioned polymorphisms and the levels of ADIPO in blood serum. MATERIAL AND METHODS: The study covered 472 girls (age: 11-19 years): 308 with the restrictive form of AN (AN) and 164 healthy girls (C). The level of ADIPO in blood serum was determined by means of the ELISA method on a Bio-Vendor, LLC (Asheville, North Carolina, USA). The DNA isolation was carried out by means of Genomic Mini AX BLOOD (SPIN). The PCR reaction was carried out in a ThermoCycle T100 thermocycler. 80-150 ng of the studied DNA and relevant F and R starters were added to the reaction mixture. The reaction products were subjected to digestion by restriction enzymes and separated on agarose gels (RFLP). RESULTS: The distribution of genotypes in the polymorphic site ADP c.45 of the ADIPO gene and ADP c.276 was similar in both groups. In both groups the T allele was most frequent in locus ADIPOQ c.45 and the G allele in locus ADIPOQ c.276. In all the study subjects collectively (AN and C) a statistically significant negative correlation between the levels of ADIPO in blood serum on one hand and body weight (r = -0.46; p < 0.0001) and BMI (r = -0.67; p < 0.0001) on the other was demonstrated. Exclusively in the AN group a significant correlation between the level of ADIPO in blood and the distribution of TG, TT, and GG alleles in loci ADIPOQ c.45 and ADIPOQ c.276 was demonstrated (p = 0.0052 and p < 0.0001, respectively). CONCLUSIONS: The genotype in loci ADIPOQ c.45 and ADIPOQ c.276 of the ADIPO gene seems to have no effect on the predisposition to AN. Girls suffering from AN with the TT genotype in loci ADIPOQ c.45 and ADIPOQ c. 276 may demonstrate higher insulin sensitivity because they have significantly higher levels of ADIPO than girls suffering from AN with other genotypes. This may be suggestive of their better adaptation to the state of malnutrition, and it has a potential effect on treatment results.

Evaluation of the frequency of RETN c.62G>A and RETN c.-180C>G polymorphisms in the resistin coding gene in girls with anorexia nervosa.

INTRODUCTION: Anorexia nervosa (AN) is a serious psychosomatic syndrome, classified as an eating disorder. AN patients strive to lose weight below the normal limits defined for a specific age and height, achieving their goal even at the expense of extreme emaciation. AN has a multifactorial aetiology. Genetic factors are believed to be significant in the predisposition to the development of AN. In girls suffering from AN significantly lower levels of resistin (RES) in blood serum are observed as compared to healthy girls. These differences may lead to a thesis that functional genetic polymorphisms in RES coding genes can be responsible for this phenomenon. In our pilot study we demonstrated significant differences in the distribution of genotypes in the locus RETN c.-180C>G of the RES gene in 67 girls with AN and 38 healthy girls. It seems reasonable to compare the frequency of polymorphisms of RETN c.62G>A and RETN c.-180C>G in the RES gene in girls with AN and in healthy subjects in a bigger cohort and to analyse correlations between individual variants of the polymorphisms referred to above and the RES levels in blood plasma. MATERIAL AND METHODS: The study covered 308 girls with the restrictive form of AN (AN) and 164 healthy girls (C) (aged 11-19 years). The RES levels in blood serum were determined by means of the ELISA method on a Bio-Vendor machine from LLC (Asheville, North Carolina, USA). The DNA isolation was carried out by means of Genomic Mini AX BLOOD (SPIN). The PCR reaction was carried out on a ThermoCycle T100 thermocycler. 80-150 ng of the studied DNA and relevant F and R starters were added to the reaction mixture. The reaction products were subjected to digestion by restriction enzymes and separated on agarose gels (RFLP). RESULTS: The average RES level in blood serum in the AN group was significantly lower (p < 0.0001) than in the C group. The distribution of genotypes in the locus RETN c.62 of the RES gene was similar in both groups. A significant difference was demonstrated in the distribution of genotypes in the polymorphic site RETN c.-180 of the RES gene between AN and C (p = 0.0145) and in the distribution of the C and G alleles in the locus RETN c.-180 (p < 0.0001). The C allele occurred significantly more frequently than the G allele in the C group as compared to the AN group. In all the study subjects jointly (AN and C) a significant positive correlation between the blood RES levels on one hand and the body mass (r = 0.42; p < 0.0001) and BMI (r = 0.61; p< 0.0001) on the other was observed. There was no correlation between the concentration of RES in blood serum and the distribution of genotypes in the loci of the resistin gene referred to above. CONCLUSIONS: The CG genotype in the locus RETN c.-180 C>G of the RES gene may constitute one of the factors predisposing to the development of AN in girls. The genotype in the loci RETN c.62 G>A and RETN c.-180 C>G of the resistin gene has no influence on the levels of this hormone in blood in AN patients.

Distribution of diandric and digynic triploidy depending on gestational age.

PURPOSE: To establish the distribution of diandric and digynic triploidy depending on gestational age. METHODS: 107 triploid samples tested prospectively in a single genetic department during a four-year period were analyzed for parental origin of triploidy by Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) (n=95) with the use of matching parental samples or by MS-MLPA (n=12), when parental samples were unavailable. Tested pregnancies were divided into three subgroups with regard to the gestational age at spontaneous pregnancy loss: <11 gestational weeks, 11-14 gestational weeks, and >14 gestational weeks. RESULTS: Diandric triploidy constituted overall 44.9% (46.5% in samples miscarried <11 gestational weeks, 64.3% in samples miscarried between 11 and 14 gestational weeks, and 27.8% in pregnancies which survived >14 gestational weeks). CONCLUSIONS: The distribution of diandric and digynic triploidy depends on gestational age. The majority of diandric triploid pregnancies is lost in the first trimester of pregnancy. In the second trimester, diandric cases are at least twice less frequent than digynic ones.

Triploid pregnancy-Clinical implications.

Triploidy is a life-limiting genetic aberration resulting from an extra haploid set of chromosomes of paternal (diandric triploidy) or maternal origin (digynic triploidy). Triploidy affects around 1%-2% of all conceptions. The majority of cases is miscarried at early developmental stages. In consequence of genomic imprinting, parental origin affects the phenotype of triploid pregnancies as well as the prevalence and spectrum of related maternal complications. Distinctive ultrasound features of both triploid phenotypes as well as characteristic patterns of biochemical markers may be useful in diagnosis. Molecular confirmation of the parental origin allows to predict the risk of complications, such as gestational trophoblastic neoplasia, hyperthyroidism, hypertension, or preeclampsia associated with the paternal origin of triploidy. Diagnosis of partial hydatidiform mole associated with diandric triploidy is challenging especially in the first trimester pregnancy loss due to the limitations of both histopathology and ultrasound. We present important clinical aspects of triploid pregnancies and indicate unresolved issues demanding further studies.

Observation of the natural course of type 3 spinal muscular atrophy: data from the polish registry of spinal muscular atrophy.

BACKGROUND: Spinal muscular atrophy (SMA) is one of the most frequent and severe genetic diseases leading to premature death or severe motor disability. New therapies have been developed in recent years that change the natural history of the disease. The aim of this study is to describe patients included in the Polish Registry of SMA, with a focus on the course of type 3 SMA (SMA3) before the availability of disease-modifying treatments. RESULTS: 790 patients with SMA were included in the registry (173 with type 1 [SMA1], 218 with type 2 [SMA2], 393 with SMA3, and six with type 4 SMA [SMA4]), most (52%) of whom were adults. Data on SMN2 gene copy number were available for 672 (85%) patients. The mean age of onset was 5 months for SMA1, 11.5 months for SMA2, and 4.5 years for SMA3. In patients with SMA3, the first symptoms occurred earlier in those with three copies of SMN2 than in those with four copies of SMN2 (3.2 years vs. 6.7 years). The age of onset of SMA3 was younger in girls than in boys (3.1 years vs. 5.7 years), with no new cases observed in women older than 16 years. Male patients outnumbered female patients, especially among patients with SMA3b (49 female vs. 85 male patients) and among patients with SMA3 with four copies of SMN2 (30 female vs. 69 male patients). 44% of patients with SMA3 were still able to walk; in those who were not still able to walk, the mean age of immobilization was 14.0 years. Patients with SMA3a (age of onset < 3 years) and three copies of SMN2 had significantly worse prognosis for remaining ambulant than patients with SMA3b (age of onset ≥ 3 years) and four copies of SMN2. CONCLUSIONS: The Registry of SMA is an effective tool for assessing the disease course in the real world setting. SMN2 copy number is an important prognostic factor for the age of onset and ambulation in SMA3. Sex and age of disease onset also strongly affect the course of SMA. Data supplied by this study can aid treatment decisions.

Small mutations in Duchenne/Becker muscular dystrophy in 164 unrelated Polish patients.

In the 164 patients with Duchenne/Becker muscular dystrophy, we found 142 different small mutations including 51 novel mutations not listed in the LOVD, the UMD-DMD, the ClinVar, and the HGMD databases. Among all mutations, nonsense mutations occurred in 45.7%, frameshift mutations in 32.9%, and splicing mutations in 19.5%. Small mutations were distributed throughout the whole dystrophin gene. Splicing mutations were twice more common in BMD patients than in DMD patients. Eighty-two percent of mothers of the males affected with DMD/BMD were found to be carriers of small mutations.

Twin pregnancies discordant for digynic triploidy - A case series.

OBJECTIVE: To analyse natural course and perinatal management in twin pregnancies discordant for digynic triploidy. CASE REPORT: We present five cases of twins discordant for digynic triploidy. Pregnancy outcome was known for three of them. In one case, premature rupture of membranes occurred at 20 gestational weeks and both fetuses were miscarried. In two other pregnancies healthy co-twins were born at term after the triploid fetuses demise at 28 and 37 weeks. No maternal complications were observed. CONCLUSION: Twin pregnancies discordant for triploidy poses a challenge for perinatal management. Expectant management should be considered in digynic triploid cases.

Usefulness of methylation-specific multiplex ligation-dependent probe amplification for identification of parental origin of triploidy.

Triploidy is a genetic aberration resulting from an extra haploid set of chromosomes of paternal (diandric) or maternal (digynic) origin. Diandric cases, opposite to digynic ones, may lead to gestational trophoblastic neoplasia (GTN) or generate maternal complications, therefore their identification is crucial, but reproducibility of traditionally used histopathological assessment is poor. The aim of the study was to analyse the usefulness of methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) with probes for two differentially methylated regions (DMR) at chromosome 11p.15.5 for identification of the parental origin of triploidy. 84 triploid DNA samples were tested with MS-MLPA: 34 paternal cases (40.5%) and 50 maternal ones (59.5%) according to the reference results of QF-PCR. Methylation ratio (MR) was calculated. Reference values proposed by the MRC-Holland for diploid samples (MR 0.8-1.2) were used. The values outside these ranges were used to diagnose parental origin of triploidy-paternal (MR > 1.2) or maternal (MR < 0.8). The effectiveness of MS-MLPA was 94.0%. The mean MR in paternal triploidy was 1.7 (SD-0.25; n = 34) compared with 0.56 in maternal triploidy (SD-0.12; n = 50). MR values in paternal and maternal triploidy did not overlap. In five samples (6.0%) parental origin of triploidy could not be accurately established by MS-MLPA, probably due to the maternal cell contamination (MCC). MS-MLPA can be used as a convenient method for distinguishing between paternal and maternal triploidy without the necessity for parental samples testing. It enables adequate selection of the paternal triploid cases for follow up in order to exclude post-molar GTN.

Interaction between polymorphisms of the oxytocinergic system genes and emotion perception in inpatients with anorexia nervosa.

OBJECTIVE: The empirical literature describes the role of the oxytocinergic system in emotion perception (EP). Variants in the oxytocin (OXT) and oxytocin receptor genes have been associated with mental disorders, including anorexia nervosa (AN), that are characterized by difficulties in socioemotional functioning. Our study aimed to examine whether variability within the genes related to OXT pathways may play a role in facial EP in inpatients with AN. METHOD: Single nucleotide polymorphisms (SNPs) of the following genes: oxytocin receptor (rs2254298, rs53576), OXT (rs6133010), OXT-arginine-vasopressin (rs2740204), CD38 (rs6449197, rs3796863), and human leucyl/cystinylaminopeptidase (rs4869317) were genotyped in 60 AN female inpatients and 60 healthy control females (HCs). Associations between genetic polymorphisms and EP as well as clinical symptoms were examined. RESULTS: The AN group showed decreased EP abilities compared with HCs. SNPs of rs2740204, rs6133010, and rs53576 were associated with differences in EP in women with AN and in HCs. The SNP of rs4869317 was associated with the level of eating disorders symptoms in HCs. CONCLUSIONS: The OXT system may be involved in EP difficulties in AN. SNPs within genes related to OXT pathways may influence EP abilities. The leucyl/cystinylaminopeptidase rs4869317 SNP may be involved in the development of eating disorders psychopathology.

Genetic polymorphisms and serum concentrations of adiponectin and resistin in anorexia nervosa and healthy controls - pilot study.

BACKGROUND: A possible role of adipokines in the regulation of body weight in patients with anorexia nervosa (AN) has been proposed. Polymorphisms in genes encoding adiponectin and resistin in AN have not been widely assessed, yet. OBJECTIVES: 1) Assessment the frequency of ADIPOQ c.45T>G, ADIPOQ c.276G>T polymorphisms in adiponectin and RETN c.62G>A, RETN c.-180C>G in resistin genes in AN patients and control group (C) 2) Analysis of correlation between these polymorphisms and serum ADP or RETN. METHODS: We examined 67 AN girls and 38 C aged 11-18. Analyses of polymorphisms in ADIPOQ and RETN genes were performed using RFLP method and adiponectin and resistin serum levels - with commercially available ELISA kits. RESULTS: In AN subjects, TT genotype in ADIPOQ c.276 polymorphism as well as GG genotype of RETN c.-180 were significantly more frequent than in CG. In ADIPOQ c.45 polymorphic site, TT alleles were the most frequent in both examined groups. In RETN c.62 GA and GG alleles distribution did not differ between the groups and the most frequently observed genotype was GG. The mean serum adiponectin level in AN was significantly higher and resistin - lower than in controls. There were no statistically significant relationships between serum adiponectin and resistin levels and allele frequency in polymorphisms ADIPOQ c.276 as well as RETN c.-180 in the examined groups. CONCLUSION: Differences in genotype frequencies of ADIPOQ c.276 and RETN c.-180 suggest a need for studies on a larger cohort of patients with AN.

Deletions, not duplications or small mutations, are the predominante new mutations in the dystrophin gene.

Examination of the carrier state was performed in 744 unrelated mothers of the Duchenne muscular dystrophy/Becker muscular dystrophy (DMD/BMD) probands with identified mutations in the dystrophin gene. Owing to that it was possible to assess frequency and type of new mutations in the gene. Contrary to the Japanese observations of Lee et al. published in this journal, we did not find significant differences in the carrier frequency between mothers of DMD and BMD patients. However, we found that new mutations in patients with deletions were significantly more frequent than in those with duplications and small mutations: of 564 unrelated patients with deletions, 236 (41.8%) carried new mutations, the respective values for duplications and small mutations were 21 of 95 patients (22.1%) and 18 of 85 patients (21.2%)-the differences highly significant (P<0.0001).

Prenatal diagnosis of Duchenne and Becker muscular dystrophies: Underestimated problem of the secondary prevention of monogenetic disorders.

AIM: The aim of this study was to analyze the influence of effective preconceptional testing for carrier status in women at risk for Duchenne and Becker muscular dystrophies (D/BMD) on the prenatal diagnosis. METHODS: A retrospective analysis of 201 prenatal tests was performed in 169 Polish women at risk, in regard to time of testing for carrier status (prior to conception or during pregnancy) and carrier status of tested women, including confirmed D/BMD carriers (n = 78; 46.2%), D/BMD non-carriers - tested for germline mosaicism risk (n = 23; 13.6%), and women at risk with uncertain carrier status (n = 68; 40.2%). RESULTS: Only 52.7% of women were tested for D/BMD carrier status prior to conception and in these women prenatal diagnosis was carried out more frequently in the first trimester of pregnancy (64.7% vs 47.8%; P = 0.035). The results of prenatal testing in male fetuses in pregnancies of confirmed D/BMD carriers and D/BMD non-carriers - tested for germline mosaicism risk were conclusive in all cases, whereas in women with uncertain carrier status, only 60.0% of results were conclusive. Eighty-five of 103 female fetuses (82.5%) were tested prenatally and in 31.8% of them fetal carrier status was confirmed. CONCLUSION: Carrier status testing in women prior to conception has a positive impact on the frequency of first-trimester prenatal diagnosis and known D/BMD carrier status on the effectiveness of prenatal diagnosis. Due to the low percentage of women tested effectively prior to conception, carrier status testing in the families at risk should be propagated (including possibility of prenatal diagnosis of female fetuses).

A rare subclinical or mild type of Becker muscular dystrophy caused by a single exon 48 deletion of the dystrophin gene.

In the material of 227 families with Becker muscular dystrophy (BMD), we found nine non-consanguineous families with 17 male individuals carrying a rare mutation-a single exon 48 deletion of the dystrophin gene-who were affected with a very mild or subclinical form of BMD. They were usually detected thanks to accidental findings of elevated serum creatine phosphokinase (sCPK). A thorough clinical analysis of the carriers, both children (12) and adults (5), revealed in some of them muscle hypotonia (10/17) and/or very mild muscle weakness (9/17), as well as decreased tendon reflexes (6/17). Adults, apart from very mild muscle weakness and calf hypertrophy in some, had no significant abnormalities on neurological assessments and had good exercise tolerance. Parents of the children carriers of the exon 48 deletion are usually unaware of their children being affected, and possibly at risk of developing life-threatening cardiomyopathy. The same concerns the adult male carriers. Therefore, the authors postulate undertaking preventive measures such as cascade screening of the relatives of the probands. Newborn screening programmes of Duchenne muscular dystrophy (DMD)/BMD based on sCPK marked increase may be considered.

First trimester pregnancy loss: Clinical implications of genetic testing.

Around 10-15% of pregnancies result in a spontaneous first trimester miscarriage, which is most frequently caused by chromosomal abnormalities, mainly aneuploidies. Genetic analysis of pregnancy loss includes conventional G-banding karyotyping and various molecular methods. Apart from variable methodological limitations, the effectiveness of genetic analysis depends on the type and quality of the tested sample. To improve the reliability of genetic testing, we present methods of appropriate collection and pre-laboratory preparation of chorionic villi from first trimester miscarriage. We also discuss issues of maternal cell contamination, placental mosaicism and reciprocal and Robertsonian translocations in the context of interpretation of the results and genetic counseling.

Impaired social cognition processes in Asperger syndrome and anorexia nervosa. In search for endophenotypes of social cognition. / Zaburzenia procesów spolecznego poznania w zespole Aspergera i jadlowstrecie psychicznym. W poszukiwaniu endofenotypów spolecznego poznania.

A growing number of publications indicates presence of significant deficits in social cognition in patients with anorexia nervosa (AN). These deficits appear to be comparable in qualitative and quantitative dimension with impairment of the same functions among people with Asperger syndrome (AS). The aim of this study is to identify subject areas in the field of impairment of social cognition processes among people with Asperger syndrome and anorexia nervosa taking into consideration the potential contribution of genetic pathways of oxytocin and vasopressin in the pathogenesis of these diseases. In the first part of the paper a systematic analysis of studies aimed at the evaluation of the processes of social cognition among patients with AN and AS has been carried out. The results of a significant number of studies confirm the presence of deficits in social cognition in AN and AS. In addition, among patients with AN and AS there exists a similar structure and distribution of the brain functions in regions responsible for social cognition. The second part of the paper describes the role of the oxytocin-vasopressin system (OT-AVP) in the processes of social cognition in AN and AS. Its genetic basis and the possible importance of single nucleotide polymorphisms within the genes: OXT, AVP, CD38, OXTR, AVPR1A and LNPEP have also been presented.

Co-incidence of Turner syndrome and Duchenne muscular dystrophy - an important problem for the clinician.

INTRODUCTION: Turner syndrome is a relatively common chromosomal disorder which affects about one in 2000 live born females. Duchenne muscular dystrophy is an X-linked recessive disorder affecting 1:3600 live born males. Considering the above, the coexistence of these two diseases may occur only anecdotally. CASE PRESENTATION: Here, we report a 4 ½ year-old female with classical 45,X Turner syndrome who also had Duchenne muscular dystrophy caused by a point mutation in the dystrophin gene (c.9055delG). The patient showed the typical phenotype of Turner syndrome including distinctive dysmorphic features (short neck, low posterior hairline, wide position of nipples), aortic coarctation and feet lymphedema. Besides, she presented with an unusually early beginning of muscular dystrophy symptoms with infantile-onset motor developmental delay, intellectual disability and early calf muscular hypertrophy. CONCLUSION: The coexistence of an X-linked recessive disorder should be considered in women affected by Turner syndrome presenting with additional atypical clinical features.

No Evidence for Association of SCO2 Heterozygosity with High-Grade Myopia or Other Diseases with Possible Mitochondrial Dysfunction.

SCO2 mutations cause recessively inherited cytochrome c oxidase deficiency. Recently Tran-Viet et al. proposed that heterozygosity for pathogenic SCO2 variants, including the common E140K variant, causes high-grade myopia. To investigate the association of SCO2 mutations with myopia, ophthalmic examinations were performed on 35 E140K carriers, one homozygous infant, and on a mouse model of Sco2 deficiency. Additionally, a screen for other putative effects of SCO2 heterozygosity was carried out by comparing the prevalence of the common E140K variant in a population of patients with undiagnosed diseases compatible with SCO2-related pathogenesis to that in a general population sample. High-grade myopia was not identified in any of the studied individuals. Of the carriers, 17 were emmetropic, and 18 possessed refractive errors. Additionally, no significant axial elongation indicative of high-grade myopia was found in mice carrying E129K (corresponding to E140K in humans) knock-in mutations. The prevalence of E140K carriers in the symptomatic cohort was evaluated as 1:103 (CI: 0.44-2.09) and did not differ significantly from the population prevalence (1:147, CI: 0.45-1.04).Our study demonstrates that heterozygosity for pathogenic SCO2 variants is not associated with high-grade myopia in either human patients or in mice.

The TREAT-NMD DMD Global Database: analysis of more than 7,000 Duchenne muscular dystrophy mutations.

Analyzing the type and frequency of patient-specific mutations that give rise to Duchenne muscular dystrophy (DMD) is an invaluable tool for diagnostics, basic scientific research, trial planning, and improved clinical care. Locus-specific databases allow for the collection, organization, storage, and analysis of genetic variants of disease. Here, we describe the development and analysis of the TREAT-NMD DMD Global database (http://umd.be/TREAT_DMD/). We analyzed genetic data for 7,149 DMD mutations held within the database. A total of 5,682 large mutations were observed (80% of total mutations), of which 4,894 (86%) were deletions (1 exon or larger) and 784 (14%) were duplications (1 exon or larger). There were 1,445 small mutations (smaller than 1 exon, 20% of all mutations), of which 358 (25%) were small deletions and 132 (9%) small insertions and 199 (14%) affected the splice sites. Point mutations totalled 756 (52% of small mutations) with 726 (50%) nonsense mutations and 30 (2%) missense mutations. Finally, 22 (0.3%) mid-intronic mutations were observed. In addition, mutations were identified within the database that would potentially benefit from novel genetic therapies for DMD including stop codon read-through therapies (10% of total mutations) and exon skipping therapy (80% of deletions and 55% of total mutations).

MLPA based detection of mutations in the dystrophin gene of 180 Polish families with Duchenne/Becker muscular dystrophy.

Duchenne/Becker muscular dystrophy (DMD/BMD) is a recessive, X-linked disorder caused by a mutation in the dystrophin gene. Deletions account for approximately 60-65% of mutations, duplications for 5-10%. The remaining cases are mainly point mutations. According to Monaco theory clinical form of the disease depends on maintaining or disrupting the reading frame. The purpose of the study was to determine frequency and location of deletions and duplications in the dystrophin gene, to determine the compliance between maintaining/disrupting the reading frame and clinical form of the disease and to check the effectiveness of MLPA (multiplex ligation-dependent probe amplification) in the detection of these mutations in hemizygous patients and heterozygous female carriers. The material is composed of combined results of molecular diagnosis carried out in years 2009-2012 in 180 unrelated patients referred with the diagnosis of DMD/BMD tested by use of MLPA. We identified 110 deletions, 22 duplication (in one patient two different duplications were detected) and 2 point mutations. Deletions involved mainly exons 45-54 and 3-21, whereas most duplications involved exons 3-18. The compliance with Monaco theory was 95% for deletions and 76% for duplications. Most of mutations in the dystrophin gene were localized in the hot spots - different for deletions and duplications. MLPA enabled their quick identification, exact localization and determination whether or not they maintained or disrupted the reading frame. MLPA was also effective in detection of deletions and duplications in female carriers.