Prevalence of the mutation C677 ? T in the methylene tetrahydrofolate reductase gene among distinct ethnic groups in Brazil

Arruda, Valder R.; Siqueira, Lúcia H.; Gonçalves, Marilda Souza; Zuben, P M von; Soares, M. C. P.; Menezes, Raimundo Camurça de; Annichino‐Bizzacchi, Joyce Maria; Costa, Fernando Ferreira

doi:10.1002/(sici)1096-8628(19980724)78:4<332::aid-ajmg5>3.0.co;2-n

Cited by 87 publications

(54 citation statements)

References 23 publications

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“…In five Brazilian Amazonian tribes of Indians, Franco et al (1998) found an allele frequency of 0.240 (homozygosity 7.8%). Arruda et al (1998) described in Amazonian Tupy Indians a frequency of 0.114 (homozygosity 1.2%). It seems that intertribal heterogeneity exists, which might be caused by isolation of small subpopulations and a high degree of consanguinity, as well as by genetic drift (Zago et al, 1996).…”

Section: Mthfr 677c>tmentioning

confidence: 99%

Geographic and Ethnic Differences in the Prevalence of Thrombophilia

Salazar‐Sánchez¹

2011

Thrombophilia

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Section: Mthfr 677c>tmentioning

confidence: 99%

Geographic and Ethnic Differences in the Prevalence of Thrombophilia

Salazar‐Sánchez¹

2011

Thrombophilia

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“…This allele frequency difference between genders was found in another study of our group (unpublished data). The T allele frequency of 3.9% did not differ from the frequency in the general Brazilian population (Arruda et al, 1998). Previous studies on the association between C677T polymorphism and NS-CL/P produced contradictory results (Shaw et …”

Section: Short Communicationmentioning

confidence: 59%

Transmission analysis of candidate genes for nonsyndromic oral clefts in Brazilian parent-child triads with recurrence

Silva¹,

Ribeiro²,

Cooper³

et al. 2006

Genet. Mol. Biol.

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Cleft lip and/or palate (CL/P) is a major congenital defect with complex etiology, including multiple genetic and environmental factors. Approximately two thirds of the cases are not accompanied by other anomalies and are called nonsyndromic (NS). In the present study, we performed transmission distortion analysis of the MSX1-CA, TGFB3-CA and MTHFR-C677T polymorphisms in 60 parent-child triads, in which the NS-CL/P affected child had at least one affected parent. No association with genes MSX1 or TGFB3 was found, but the results were suggestive of an association of the MTHFR-C677T polymorphism with NS-CL/P. Nonsyndromic cleft lip and/or palate (NS-CL/P) affect about 1/700 livebirths, with wide variability concerning geographic distribution, ethnic background and socioeconomic status (Murray, 2002). The etiology is complex, including multiple genetic and environmental factors. The MSX1 and TGFB3 genes have been suggested as candidate genes based on animal models (Satokata and Maas, 1994;Kaartinen et al., 1995;Proetzel et al., 1995) and association studies in humans with genes MSX1, TGFB3 and MTHFR have pointed to the involvement of these genes in NS-CL/P etiology (Maestri et al., 1997;Lidral et al., 1998;Romitti et al., 1999;Mills et al., 1999; Wyszynsky and Diehl, 2000;Beaty et al., 2001). The MSX1 gene maps to chromosome 4p16. Animal models indicate that this gene plays a role in craniofacial anomalies, leading to a clefting phenotype. Van den Boogaard et al. (2000) identified a stop codon in the MSX1 gene in a three-generation Dutch family with tooth agenesis and combinations of CP only and CLP, providing further evidence for the involvement of this gene in orofacial clefting. Jezewski et al. (2003) sequenced the whole MSX1 gene in a large sample of NS-CL/P patients from different geographic regions, and found mutations in about 2% of the cases.The TGFB3 gene maps to 14q24. Animal model studies demonstrated that TGFB3 plays a role in CP (Kaartinen et al., 1995;1997;Proetzel et al., 1995; Sanford et al., 1997), andLidral et al. (1998) showed an association between TGFB3 markers and NS-CP.The MTHFR gene maps to 1p36.1, and plays a key role in the metabolism of folate by reducing methylenetrahydrofolate to 5-methyltetrahydrofolate, the primary methyl donor for methionine synthesis. The C677T nucleotide variant in the MTHFR gene results in a thermally unstable protein with reduced activity, leading to elevated plasma homocysteine levels. Considerable heterogeneity in the prevalence of the C677T polymorphism throughout the world was reported (Pepe et al., 1998).The present work aimed to investigate if genes TGFB3, MSX1 and MTHFR-C677T are involved in the etiology of NS-CLP, by testing 60 patients, all with an affected parent. We utilized a nuclear family-based approach, to determine for each form of clefting whether these genes were in linkage disequilibrium, as measured by transmission distortion.A total of 60 triads, each one including an affected child and at least one affected parent, were studied. Of...

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“…However, this is an unlikely hypothesis because, using a similar criteria selection, we were able to demonstrate that mutations that were highly prevalent among Caucasians were not identified among African descents [41][42][43].…”

Section: Discussionmentioning

confidence: 88%

Genetic variability of platelet glycoprotein Ibα gene

et al. 2004

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Platelet membrane glycoprotein (GP) Ibα is a critical component of platelet adhesion complex to subendothelium structures following tissue injury or pathological surfaces, such as atherosclerotic plaques. Polymorphisms of the GPIbα gene have been associated with a high risk for occlusive vascular disease, and its distribution varies considerably among distinct populations. These polymorphisms comprise the human platelet antigen (HPA)‐2 system, the −5C/T dimorphism of the Kozak sequence, and the variable number of tandem 39‐bp repeats (VNTR). Here we report the prevalence of the GPIbα gene polymorphisms among Brazilians, a highly ethnically diverse population. We analyzed 492 subjects of European, African, or Indigenous origin. It was possible to determine ten distinct haplotypes. The most common (∽40%) haplotype was the Kozak‐TT/HPA‐2aa/VNTR‐CC for both Caucasian and African descent. However, among Indigenous, Kozak‐TT/HPA‐2aa/VNTR‐CC and Kozak‐TC/HPA‐2aa/VNTR‐CC were equally present. Although a strong linkage disequilibrium between VNTR and HPA‐2 polymorphism had also been observed, here we determined incomplete linkage disequilibrium in 10% of subjects from all ethnic groups. VNTR‐E, a rare variant lacking the 39‐bp repeat, was identified in two unrelated subjects, and functional platelet studies revealed no abnormalities. The VNTR‐A allele, the largest variant containing four copies of the repeats, was not identified in this population. However, homozygosity for the VNTR‐A allele (Kozak‐TT/HPA‐2aa/VNTR‐AA) was determined in two distinct species of nonhuman primates. These results suggest a greater complex evolutionary mechanism in the macroglycoprotein region of the GPIbα gene and may be useful in the design of gene–disease association studies for vascular disease. Am. J. Hematol. 77:107–116, 2004. © 2004 Wiley‐Liss, Inc.

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Prevalence of the mutation C677 ? T in the methylene tetrahydrofolate reductase gene among distinct ethnic groups in Brazil

Cited by 87 publications

References 23 publications

Geographic and Ethnic Differences in the Prevalence of Thrombophilia

Geographic and Ethnic Differences in the Prevalence of Thrombophilia

Transmission analysis of candidate genes for nonsyndromic oral clefts in Brazilian parent-child triads with recurrence

Genetic variability of platelet glycoprotein Ibα gene

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