RESUMEN

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.

Asunto(s)

Huesos/anomalías , Facies , Glaucoma/diagnóstico , Glaucoma/genética , Iris/anomalías , Adulto , Huesos/diagnóstico por imagen , Anomalías del Ojo/diagnóstico , Anomalías del Ojo/genética , Femenino , Genes Recesivos , Humanos , Masculino , Radiografía , Hermanos , Síndrome

RESUMEN

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.

Asunto(s)

Anomalías Múltiples/genética , Dedos/anomalías , Hipertelorismo/genética , Columna Vertebral/anomalías , Anomalías Múltiples/patología , Adolescente , Adulto , Niño , Facies , Salud de la Familia , Femenino , Genes Dominantes , Humanos , Hipertelorismo/patología , Masculino , México , Linaje , Disrafia Espinal/genética , Disrafia Espinal/patología

RESUMEN

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.

Asunto(s)

Hipertricosis , Enfermedades Genéticas Congénitas/genética , Humanos , Hipertricosis/genética , Hipertricosis/patología

Asunto(s)

Análisis de Secuencia por Matrices de Oligonucleótidos

RESUMEN

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 (0.06

Asunto(s)

Mutación Missense/genética , Defectos del Tubo Neural/enzimología , Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH/genética , Polimorfismo Genético , ADN/análisis , Análisis Mutacional de ADN , Femenino , Genotipo , Humanos , Masculino , Metilenotetrahidrofolato Reductasa (NADPH2) , México/epidemiología , Defectos del Tubo Neural/etnología , Defectos del Tubo Neural/genética , Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH/sangre , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción

RESUMEN

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.

Asunto(s)

Biología Molecular , Interfaz Usuario-Computador , Análisis Costo-Beneficio , Países en Desarrollo , Humanos , México , Biología Molecular/economía

RESUMEN

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.

Asunto(s)

Factor IX/genética , Mutación de Línea Germinal , Hemofilia B/genética , Femenino , Eliminación de Gen , Humanos , Masculino , México , Mutación Puntual

RESUMEN

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.

RESUMEN

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.

Asunto(s)

Etnicidad/genética , Variación Genética/genética , Repeticiones de Minisatélite , Polimorfismo Genético/genética , Secuencias Repetidas en Tándem , Consanguinidad , Frecuencia de los Genes , Humanos , Indígenas Centroamericanos/genética , México

RESUMEN

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.

Asunto(s)

Alelos , Frecuencia de los Genes , Población Blanca/genética , Población Negra/genética , Brasil , Electroforesis en Gel de Poliacrilamida , Femenino , Hispánicos o Latinos/genética , Humanos , Indígenas Norteamericanos/genética , Masculino , México , Polimorfismo Genético , Polimorfismo de Longitud del Fragmento de Restricción

RESUMEN

A search for mutations in exons 6, 7, 9 and 12 of the PS1 gene in four Mexican families with Early-Onset (36-40 years) Alzheimer Disease yielded the discovery in one family of a T-->C mismatch in exon 7 which correspond to nucleotide 760 of cDNA, leading to a Leu171Pro mutation. The pedigree analysis and the literature data strongly suggest an etiopathogenic relationship of the mutation with the disorder.

Asunto(s)

Enfermedad de Alzheimer/genética , Proteínas de la Membrana/genética , Mutación Missense , Adulto , Edad de Inicio , Sustitución de Aminoácidos , Humanos , Leucina , México , Linaje , Reacción en Cadena de la Polimerasa , Presenilina-1 , Prolina

RESUMEN

Diesel or its derivatives could have aneuploidogenic and/or clastogenic activity. Hence, the genotoxicity of diesel gases has been studied, considering exposure to them as potentially carcinogenic. The results obtained by different authors suggest the need to know the effects of direct and chronic exposure to diesel in humans, as in the case of the street workers called 'firebreathers' who fill their buccal cavity with diesel and then spread it to a burning torch many times during the day in order to give a 'dragon show' for 5 h a day and 6 days a week. The buccal samples of eight firebreathers were collected, processed and scored according to the criterion established by Tolbert et al., 1992 and then compared with positive and negative control groups. The results revealed that diesel was not micronucleogenic although it induces some nuclear abnormalities.

Asunto(s)

Gasolina/efectos adversos , Mucosa Bucal/efectos de los fármacos , Mutágenos/efectos adversos , Exposición Profesional/efectos adversos , Adulto , Aberraciones Cromosómicas , Femenino , Humanos , Masculino , Pruebas de Micronúcleos , Persona de Mediana Edad , Mucosa Bucal/ultraestructura

RESUMEN

We carried out molecular analysis of 80 chromosomes from 40 unrelated Mexican patients with a diagnosis of cystic fibrosis. The study was performed in two PCR steps: a preliminary one to identify mutation delta F508, the most frequent cause of cystic fibrosis worldwide, and the second a reverse dot-blot with allele-specific oligonucleotide probes to detect 15 additional common mutations in the Caucasian population. A frequency of 45% for delta F508 was found, making it the most common in our sample of Mexican patients. Another five mutations (G542X, 3,849 + 10 kb C-->T, N1303K, SN549N, and 621 + 1 G-->T) were detected, and those accounted for 11.25%. The remaining mutations (43.75%) were undetectable with the methodology used.

Asunto(s)

Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Fibrosis Quística/genética , Humanos , México , Mutación

RESUMEN

The hypertrichosis and osteochondrodysplasia syndrome is a rare entity with clinical findings including macrosomia at birth cardiomegaly. Autosomal recessive inheritance is presumed based on the report of two affected sibs born to healthy parents. Here we report on four new patients with their follow-up data, as well as on one of the four cases from the original report. Comparison of all eight cases indicates that they share 50% of clinical and radiological changes. This report contributes to the further delineation of this newly recognized syndrome.

Asunto(s)

Anomalías Múltiples/genética , Cardiomegalia/congénito , Hipertricosis/congénito , Osteocondrodisplasias/congénito , Adolescente , Cardiomegalia/diagnóstico , Cardiomegalia/genética , Niño , Preescolar , Femenino , Humanos , Hipertricosis/diagnóstico , Hipertricosis/genética , Masculino , Osteocondrodisplasias/diagnóstico , Osteocondrodisplasias/diagnóstico por imagen , Osteocondrodisplasias/genética , Fenotipo , Radiografía , Síndrome , Rayos X

RESUMEN

The purpose of the present study was to investigate the range of micronucleated erythrocytes (MNE) in peripheral blood from splenectomized patients with and without genotoxic chemotherapy. The erythrocytes were stained with Wright and Giemsa for microscopic observation. To estimate the number of MNE, two series of 10000 erythrocytes per sample were analyzed and averaged. The results expressed as mean +/- standard deviation were as follows: control patients with genotoxic chemotherapy (n = 6) 2.5 +/- 1.5 (range 1 to 5 MNE); splenectomized patients with genotoxic chemotherapy (n = 7) 65.2 +/- 17.7 (range: 47-108) MNE and splenectomized patients without genotoxic chemotherapy (n = 13) 29.5 +/- 5.8 MNE; (range: 18.5-35.6). The MNE number in the patients treated with genotoxic chemotherapy depended on the type of drugs utilized: cyclophosphamide, mitoxantrone, vincristine, busulphan, cytosine arabinoside and hydroxyurea. Upon these results, it is suggested that splenectomized people could be useful in monitoring exposures, and the baseline MNE level would serve as each person's pre-exposure control when either chronic or acute exposure to environmental mutagens is investigated.

Asunto(s)

Antineoplásicos/efectos adversos , Eritrocitos/ultraestructura , Enfermedades Hematológicas/sangre , Micronúcleos con Defecto Cromosómico , Neoplasias/sangre , Adulto , Antineoplásicos/uso terapéutico , Femenino , Enfermedades Hematológicas/tratamiento farmacológico , Enfermedades Hematológicas/cirugía , Humanos , Masculino , Neoplasias/tratamiento farmacológico , Neoplasias/cirugía , Esplenectomía

RESUMEN

In this paper we report the results of a study to determine the frequencies of spontaneous micronucleated erythrocytes (MNE) in peripheral blood of 35 mammalian species. The main goal was to find mammals with a high spontaneous frequency of MNE that could, therefore, be good candidates for biomonitoring genotoxic agents in their natural habitat. We obtained 187 peripheral blood samples, but in 13 of the species we could only sample one individual. A wide range in the number of MNE (1/434 to 0/40,000 erythrocytes) was observed. Since the number of individuals per species is not high enough, this results should be cautiously considered. The cat, mouse, giraffe, pig, opossum and capuchin monkey seem to be suitable species for biomonitoring for genotoxic events.

Asunto(s)

Contaminantes Ambientales/toxicidad , Eritrocitos/efectos de los fármacos , Mamíferos/genética , Mutágenos/toxicidad , Animales , Eritrocitos/metabolismo , Mamíferos/sangre , Pruebas de Micronúcleos , Especificidad de la Especie

RESUMEN

Clinically, two unrelated patients, an adult male and a female child, coming from non-consanguineous parents, presented dwarfism, peculiar facies, with blepharophimosis, mongoloid slanted eyes, abundant eyebrows and eyelashes, harsh voice and short hands and feet. Radiologically, they presented brachymetacarpalia, brachymetatarsalia, and brachyphalangia of all fingers and toes, shortened and broadened long bones with normal morphology, hypoplastic pelvis and shape anomalies of the vertebral bodies. The clinical and radiological concordance and the differential diagnosis, mainly with acromicric dysplasia, allow the characterization of a distinctive osteochondrodysplasia probably due to an autosomal dominant mutation.

Asunto(s)

Osteocondrodisplasias , Adulto , Niño , Femenino , Humanos , Masculino , Osteocondrodisplasias/diagnóstico por imagen , Osteocondrodisplasias/genética , Radiografía , Síndrome

RESUMEN

Five polymorphic index markers were analyzed by polymerase chain reaction (PCR) to ascertain the parental origin of the extra X chromosomes in seven polysomic cases (one 49,XXXXX, three 49,XXXXY, two 48,XXXY, and one 48,XXYY). All four X chromosomes in 49, X polysomies were maternal in origin and the extra X chromosomes in 48 X polysomies were paternal. In each case the multiple X chromosomes were contributed by a single parent. Taken together with previously reported cases, these data support a single mechanism of sequential nondisjunction during either maternal or paternal gametogenesis as the cause of higher order sex chromosome polysomy.

Asunto(s)

Aneuploidia , Cromosoma X , Adulto , ADN/análisis , Femenino , Humanos , Masculino , No Disyunción Genética , Padres , Linaje , Reacción en Cadena de la Polimerasa , Polimorfismo Genético

RESUMEN

The Aarskog syndrome is a true MCA syndrome with X-linked recessive inheritance. The clinical phenotype, and its evolution with age, have been well documented in the past. Few data are reported on the radiological skeletal changes and findings. The purpose of the present paper is to describe the clinical and radiological findings in two brothers with Aarskog syndrome and to further delineate the radiological characteristics of this condition. The main findings are asynchronic and delayed bone age, shortened long tubular bones with wide metaphyses, brachyphalangy, hypoplasia of the middle phalanges of the fifth fingers, short and broad first metacarpals and metatarsals and pelvic hypoplasia.

Asunto(s)

Anomalías Múltiples/genética , Huesos Faciales/anomalías , Dedos/anomalías , Genitales Masculinos/anomalías , Aberraciones Cromosómicas Sexuales/genética , Cráneo/anomalías , Cromosoma X , Anomalías Múltiples/diagnóstico por imagen , Determinación de la Edad por el Esqueleto , Enfermedades del Desarrollo Óseo/diagnóstico por imagen , Enfermedades del Desarrollo Óseo/genética , Huesos/diagnóstico por imagen , Preescolar , Enanismo/diagnóstico por imagen , Enanismo/genética , Huesos Faciales/diagnóstico por imagen , Dedos/diagnóstico por imagen , Genes Recesivos/genética , Genitales Masculinos/diagnóstico por imagen , Humanos , Masculino , Cráneo/diagnóstico por imagen , Síndrome

RESUMEN

The oral-facial-digital (OFD) syndromes constitute a heterogeneous group of entities usually associated with certain features that permit a specific diagnosis. This report refers to a 10-month-old girl with cleft palate, mesomelic limb shortening, oligopolydactyly, and fibular aplasia. Since this combination has not been described previously, it is proposed as a distinct type of oral-facial-digital syndrome, and we suggest mutations of homeotic genes to explain some abnormalities present in the OFD syndromes.

Asunto(s)

Síndromes Orofaciodigitales/patología , Femenino , Humanos , Lactante , Fenotipo