RESUMO
Three sibs with congenital glaucoma, skeletal anomalies, and peculiar facial appearance were studied. At birth, enlarged eyes and corneae were present in the proposita and her two brothers due to congenital glaucoma secondary to iridogoniodysgenesis (IGD). The purpose of this article is to describe the second familial case with IGD and skeletal anomalies as the family previously described by García-Cruz et al. in 1990, corroborating this new distinct dysmorphic syndrome with probable autosomal recessive inheritance.
Assuntos
Osso e Ossos/anormalidades , Fácies , Glaucoma/diagnóstico , Glaucoma/genética , Iris/anormalidades , Adulto , Osso e Ossos/diagnóstico por imagem , Anormalidades do Olho/diagnóstico , Anormalidades do Olho/genética , Feminino , Genes Recessivos , Humanos , Masculino , Radiografia , Irmãos , SíndromeRESUMO
A Mexican family is presented with the main clinical features of camptodactyly, a distinctive facial appearance because of ocular hypertelorism, telecanthus, symblepharon and spinal defects. Other clinical manifestations included: multiple nevi, simplified ears, retrognathia, congenital shortness of the sternocleidomastoid muscle, thin hands and feet, a small penis and mild mental retardation. Radiographic studies revealed spina bifida occulta at cervical and dorso-lumbar levels, increased bone trabeculae, cortical thickening and delayed bone age. The presence of five affected members through four generations suggests autosomal dominant inheritance although no male-to-male transmission was documented. The authors propose this as a new entity, and have designated it Guadalajara camptodactyly type III.
Assuntos
Anormalidades Múltiplas/genética , Dedos/anormalidades , Hipertelorismo/genética , Coluna Vertebral/anormalidades , Anormalidades Múltiplas/patologia , Adolescente , Adulto , Criança , Fácies , Saúde da Família , Feminino , Genes Dominantes , Humanos , Hipertelorismo/patologia , Masculino , México , Linhagem , Disrafismo Espinal/genética , Disrafismo Espinal/patologiaRESUMO
Hypertrichosis is a rare condition characterized by excessive growth of hair (terminal, vellus or lanugo) in areas of the body that are not predominantly androgen dependent, and it is independent of age, race or sex. It can be congenital, late-onset, generalized, localized, inherited or acquired. More than 50 different OMIM entries related to hypertrichosis exist, few of them with a localized gene locus or with a candidate gene. The review of generalized hypertrichoses from a historical point of view, including a review of their clinical and genetic features, shows heterogeneity with at least nine different entities. A short analysis of other forms of hypertrichosis is presented.
Assuntos
Hipertricose , Doenças Genéticas Inatas/genética , Humanos , Hipertricose/genética , Hipertricose/patologiaRESUMO
The C677T mutation of the methylenetetrahydrofolate reductase (MTHFR) gene, associated with the thermolabile form of the enzyme, has reportedly been found to be increased in neural-tube defects (NTD), though this association is still unclear. A group of 107 mestizo parents of NTD children and five control populations: 101 mestizo (M), 50 Huichol (H), 38 Tarahumara (T), 21 Purepecha (P) and 20 Caucasian (C) individuals were typed for the MTHFR C677T variant by the PCR/RFLP (HinfI) method. Genotype frequencies were in agreement with the Hardy-Weinberg expectations in all six populations. Allele frequency (%) of the C677T variant was 45 in NTD, 44 in M, 56 in H, 36 in T, 57 in P, 35 in C. Pairwise inter-population comparisons of allele frequency disclosed a very similar distribution between NTD and M groups (exact test, P=0.92). Among controls, differences between M and individual native groups were NS (0.06Assuntos
Mutação de Sentido Incorreto/genética
, Defeitos do Tubo Neural/enzimologia
, Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética
, Polimorfismo Genético
, DNA/análise
, Análise Mutacional de DNA
, Feminino
, Genótipo
, Humanos
, Masculino
, Metilenotetra-Hidrofolato Redutase (NADPH2)
, México/epidemiologia
, Defeitos do Tubo Neural/etnologia
, Defeitos do Tubo Neural/genética
, Oxirredutases atuantes sobre Doadores de Grupo CH-NH/sangue
, Reação em Cadeia da Polimerase
, Polimorfismo de Fragmento de Restrição
RESUMO
The limited resources of developing countries are forcing them to search for different options to keep up with the accelerating pace of research into genetic medicine. In Mexico, one such option is the Mexican Network of Molecular Biomedicine (MNMB). With the Internet as a means of communication and a source of information, the MNMB aims to provide a program based on cooperation, high-quality service and patient care.
Assuntos
Biologia Molecular , Interface Usuário-Computador , Análise Custo-Benefício , Países em Desenvolvimento , Humanos , México , Biologia Molecular/economiaRESUMO
The haplotypes of 97 beta(A) independent chromosomes from a Mexican Huichol Native American group were analyzed. The analysis also included 87 beta(A) chromosomes from a Mexican Mestizo population previously studied. Among Huichols, eight different 5' beta haplotypes (5Hps) were observed, with types 1(+ - - - -), 13(+ + + - +) and 2(- + + - +) at frequencies of 0.794, 0.093, and 0.041, respectively. In Mestizos, 17 5Hps were found, types 1, 3(- + - + +), 2, 5(- + - - +) and 9(- - - - -) being the most common at frequencies of 0.391, 0.172, 0.092, 0.069, and 0.046, respectively. 3' haplotype (3Hps) frequency distributions were 0.443(+ +), 0.083(+ -), and 0.474(- +) in Huichols and 0.563(+ +), 0.149(+ -), and 0.287(- +) in Mestizos. Pairwise comparison for both haplotype distributions between the two populations showed significant differences. Pairwise distributions of 3Hps for Huichols were compared with nine worldwide populations, three African, two Asian, two Melanesian, one Caucasian, and one United States Native American. The distributions of the Huichol were different (P < 0.05) from all populations except the Native American. Nei's genetic distances showed the Huichols to be closer to the Native Americans, followed by Melanesians from Vanuatu and Asians; Africans were the farthest. The 5Hp distributions in Mexicans were also compared with 23 worldwide populations (including African, Native American, Asian, Caucasian, and Pacific Islanders). Huichol distributions were different (P < 0.05) from all other populations except Koreans. The Mestizo distribution was also different from the others, except three Caucasian groups. Nei's genetic distance between the same populations disclosed that the Huichols are in relatively close proximity to five out of six Asian populations considered. The same analysis with grouped worldwide populations showed Native Americans as population closest to the Huichols, followed by Pacific Islanders and Asians. Present observations are consistent with an important Asian contribution to the Huichol genome in this chromosomal region. Am. J. Hum. Biol. 12:201-206, 2000. Copyright 2000 Wiley-Liss, Inc.
RESUMO
Allele distributions of two polymorphisms with variable number of tandem repeats (VNTR), D1S80 and APOB, and four polymorphisms with short tandem repeats (STR), VWA, TH01, CSF1PO, and HPRTB, were analyzed in three Mexican ethnic groups: Huichol, Purepecha, and Tarahumara. Genotype distribution was in agreement with Hardy-Weinberg expectations for each locus and ethnic group. Heterozygosity (H), power of discrimination, and probability of exclusion were estimated. The three groups presented some distinctive genetic features: (1) a diminished genetic diversity (H = 66.8% to 73.4%) and mean number of alleles by locus (5.8 to 6.3) in comparison with Mexican mestizos (H = 78.3%, 10.5 alleles/locus), and (2) uneven allele distributions as evidenced by "distinctive alleles" with high frequencies, especially in the Tarahumara and the Huichol. Genetic relatedness analysis included data from a previously typed mestizo population, the largest and most widely distributed population in Mexico. Allele distribution differentiation was observed among all four groups, except between mestizo and Purepecha (p > 0.05), which was interpreted as indicating a larger Spanish component in the Purepecha as a result of gene flow effects. Although intrapopulation inbreeding (FIS) was not significant, heterozygote deficiency in the total population (FIT) and divergence among populations (FST) were significant (p < 0.05). Genetic distances displayed a closer relationship among mestizos, Purepechas, and Huichols in relation to Tarahumaras. Correlation between the observed genetic features and the geographic isolation level points to genetic drift as the main cause of differentiation among these Mexican populations.
Assuntos
Etnicidade/genética , Variação Genética/genética , Repetições Minissatélites , Polimorfismo Genético/genética , Sequências de Repetição em Tandem , Consanguinidade , Frequência do Gene , Humanos , Indígenas Centro-Americanos/genética , MéxicoRESUMO
The factor IX gene (F9) is a valuable model for studying germ-line mutations. Nine mutations were detected in nine Mexican patients with hemophilia B by direct sequencing using genomic amplification with transcript sequencing (GAWTS): six single base changes, one micro-deletion, and two large deletions. Germline origins of mutations were found in three of six families with sporadic cases. Curiously, the four independent single base substitutions which were not at CpG dinucleotides occurred at only two different nucleotide positions (17,678 and 17,747) one transition and one transversion at each. The two remaining substitutions were identical changes at a CpG dinucleotide, but were determined to be independent by germline origin analysis. A statistical analysis suggests that the independent recurrence of mutations at these locations may reflect an unusual aspect of F9 mutagenesis in the Mexican population. These data raise the possibility of population-specific differences in human germline mutations.
Assuntos
Fator IX/genética , Mutação em Linhagem Germinativa , Hemofilia B/genética , Feminino , Deleção de Genes , Humanos , Masculino , México , Mutação PuntualRESUMO
Six amplified fragment length polymorphisms or Amp-FLPs, two VNTRs (D1S80 and APO-B) and four STRs (VWA, TH01, CSF1PO and HPRTB), were typed in a Mexican population of the Jalisco state by means of non-denaturing polyacrylamide gel electrophoresis (native PAGE) in standard gel units and silver staining. Genotype distribution was in agreement with Hardy-Weinberg expectations (HWE) for all six markers. Heterozygosity ranged from 70.6 to 83.5%, the cumulated chance of exclusion (CE) and power of discrimination (PD) were 99.4 and 99.99%, respectively. STRs and D1S80 allele frequency distributions (AFD) were similar (P > 0.05) to U.S. Hispanics, but different to U.S. Caucasians and African-Americans. APO-B exhibited similarities with White Brazilians, Spaniards, but differences (P < 0.05) with Amerindian and Black Brazilians.