13 research outputs found

    New genetic loci link adipose and insulin biology to body fat distribution.

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    Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

    HTT haplogroups in Finnish patients with Huntington disease

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    Abstract Objective: To study genetic causes of the low frequency of Huntington disease (HD) in the Finnish population, we determined HTT haplogroups in the population and patients with HD and analyzed intergenerational Cytosine-Adenosine-Guanosine (CAG) stability. Methods: A national cohort of patients with HD was used to identify families with mutant HTT (mHTT). HTT haplogroups were determined in 225 archival samples from patients and from 292 population samples. CAG repeats were phased with HTT haplotypes using data from parent-offspring pairs and other mHTT carriers in the family. Results: The allele frequencies of HTT haplotypes in the Finnish population differed from those in 411 non-Finnish European subjects (p &lt; 0.00001). The frequency of haplogroup A was lower than that in Europeans and haplogroup C was higher. Haplogroup A alleles were significantly more common in patients than in controls. Among patients with HD haplotypes A1 and A2 were more frequent than among the controls (p = 0.003). The mean size of the CAG repeat change was +1.38 units in paternal transmissions being larger than that (−0.17) in maternal transmissions (p = 0.008). CAG repeats on haplogroup A increased by 3.18 CAG units in paternal transmissions, but only by 0.11 units in maternal transmissions (p = 0.008), whereas haplogroup C repeat lengths decreased in both paternal and maternal transmissions. Conclusions: The low frequency of HD in Finland is partly explained by the low frequency of the HD-associated haplogroup A in the Finnish population. There were remarkable differences in intergenerational CAG repeat dynamics that depended on HTT haplotype and parent gender

    Huntingtonin tauti

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    TiivistelmĂ€ Huntingtonin tauti on vallitsevasti periytyvĂ€, HTT-geenin virheen aiheuttama etenevĂ€ hermoston rappeumasairaus. HTT-geeni on kehityksellisesti vanhaa perua, ja sillĂ€ on useita tehtĂ€viĂ€ solussa. Virheellisen geenituotteen toksisuus on taudin synnylle oleellista ja vĂ€littyy monien mekanismien kautta. Taudin esiintyvyys on suurinta valkoihoisen vĂ€estön joukossa, mutta Suomessa tauti on harvinaisempi kuin muissa lĂ€nsieurooppalaisperĂ€isissĂ€ vĂ€estöissĂ€. Suomessa esiintyvyys on 2,12/100 000 henkilöÀ. Ydinoireita ovat liikehĂ€iriö, erityisesti korea, kognitiivinen oireisto sekĂ€ mieliala- ja kĂ€ytösoireet. Lapsuus- ja nuoruusiĂ€ssĂ€ ilmenevĂ€lle taudille ominaista ovat rigiditeetin ja epileptisten kohtausten yleisyys, kognitiivisen oirekuvan korostuminen sekĂ€ korean suhteellinen vĂ€hĂ€isyys, ja ilmiasu poikkeaakin aikuisiĂ€ssĂ€ alkavasta taudista. Oireenmukaista hoitoa ohjaava nĂ€yttö on vĂ€hĂ€istĂ€. Taudin kulkuun vaikuttavaa hoitoa ei ole kĂ€ytettĂ€vissĂ€.Abstract Huntington’s disease (HD) is an autosomally dominantly inherited lethal neurodegenerative disease. It is caused by an elongated CAG tract in the phylogenetically ancient HTT gene that has many interaction partners and tasks in the cell. HD is most prevalent among populations of Caucasian descent, but in Finland it is rarer (2.12/100 000) than in caucasian populations. The disease is characterized by a triad of motor, cognitive and behavioral signs and symptoms. Juvenile onset HD differs from the adult-onset disease in many respects. Disease modifying therapy is not available and studies about symptomatic treatment are scarce

    PGAP2 Mutations, Affecting the GPI-Anchor-Synthesis Pathway, Cause Hyperphosphatasia with Mental Retardation Syndrome

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    Recently, mutations in genes involved in the biosynthesis of the glycosylphosphatidylinositol (GPI) anchor have been identified in a new subclass of congenital disorders of glycosylation (CDGs) with a distinct spectrum of clinical features. To date, mutations have been identified in six genes (PIGA, PIGL, PIGM, PIGN, PIGO, and PIGV) encoding proteins in the GPI-anchor-synthesis pathway in individuals with severe neurological features, including seizures, muscular hypotonia, and intellectual disability. We developed a diagnostic gene panel for targeting all known genes encoding proteins in the GPI-anchor-synthesis pathway to screen individuals matching these features, and we detected three missense mutations in PGAP2, c.46C>T, c.380T>C, and c.479C>T, in two unrelated individuals with hyperphosphatasia with mental retardation syndrome (HPMRS). The mutations cosegregated in the investigated families. PGAP2 is involved in fatty-acid GPI-anchor remodeling, which occurs in the Golgi apparatus and is required for stable association between GPI-anchored proteins and the cell-surface membrane rafts. Transfection of the altered protein constructs, p.Arg16Trp (NP_001243169.1), p.Leu127Ser, and p.Thr160Ile, into PGAP2-null cells showed only partial restoration of GPI-anchored marker proteins, CD55 and CD59, on the cell surface. In this work, we show that an impairment of GPI-anchor remodeling also causes HPMRS and conclude that targeted sequencing of the genes encoding proteins in the GPI-anchor-synthesis pathway is an effective diagnostic approach for this subclass of CDGs

    Regulations and practices of genetic counselling in 38 European countries: the perspective of national representatives

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    The aim of this article is to review the national regulations and practices of genetic counselling in 38 European countries, and to examine how well they intersect the ideals of genetic counselling defined in international guidelines. Using an electronic survey, representatives of the National Societies of Human Genetics in 29 countries, and appropriate contact persons for the field of genetic counselling in 9 other countries, were asked about the regulations and practices. The answers showed that consent, confidentiality, genetic counselling in the context of prenatal diagnosis, those professionals who may perform genetic counselling, and non-directiveness were the topics most often either agreed upon among professionals or regulated in those countries. These are also among the key aspects of ideal genetic counselling, based on international guidelines. Counselling in the context of susceptibility testing for multifactorial diseases, counselling people from ethnic minorities and recontacting the counsellees, on the contrary, were topics regulated or guided by generally applied practices in only few countries. Many of the answers expressed a desire for more regulation of genetic counselling, and that more uniform practices of education and organization of genetic counselling would be welcome in Europe

    Germline mutations in FH predispose to dominantly inherited uterine fibroids, skin leiomyomata and papillary renal cell cancer

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    Uterine leiomyomata (fibroids) are common and clinically important tumors, but little is known about their etiology and pathogenesis. We previously mapped a gene that predisposes to multiple fibroids, cutaneous leiomyomata and renal cell carcinoma to chromosome 1q42.3-q43 (refs 4-6). Here we show, through a combination of mapping critical recombinants, identifying individuals with germline mutations and screening known and predicted transcripts, that this gene encodes fumarate hydratase, an enzyme of the tricarboxylic acid cycle. Leiomyomatosis-associated mutations are predicted to result in absent or truncated protein, or substitutions or deletions of highly conserved amino acids. Activity of fumarate hydratase is reduced in lymphoblastoid cells from individuals with leiomyomatosis. This enzyme acts as a tumor suppressor in familial leiomyomata, and its measured activity is very low or absent in tumors from individuals with leiomyomatosis. Mutations in FH also occur in the recessive condition fumarate hydratase deficiency, and some parents of people with this condition are susceptible to leiomyomata. Thus, heterozygous and homozygous or compound heterozygous mutants have very different clinical phenotypes. Our results provide clues to the pathogenesis of fibroids and emphasize the importance of mutations of housekeeping and mitochondrial proteins in the pathogenesis of common types of tumor
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