Determinación de la cigocidad del gen RHD

Abstract

ABSTRACT: The study of couples in RHD cigocidad of RhD negative women is important for clinical genetic counseling pregestational and gestational in families with a history of hemolyticdisease of the newborn. The objective was to identify the status of the gene RHD cigocidad subjects RhD positive, traditional PCR-RFLP and real-time PCR in families residing in the Valley of Mexico, as well as determining the consistency of the RHD gene cigocidad between phenotype Rh system and molecular tests. Material and Methods. Case-control study, transverse and descriptive. The cases were composed of families where the mother is RhD negative and RhD positive and your partner at least one biological child evaluated. Controls were families with both parents RhD positive and at least one child studied. We determined the phenotype of Rh (D, C, c, e, e) and specific sequences of the gene RHD (3 'UTR exon 10, exon 7, exon intron4- 4/RHDψ by real-time PCR and PCR boxes RH -RFLP). Results. We evaluated 228 individuals, 122 parents and 106 children belonging to 61 families (61 mothers and 61 fathers). Families were 28 cases with 44 children and 33 families with 62 children of controls. The most frequent positive RhD phenotypes of the population studied were CcDee (33.2%), CCDee (24.1%) and CcDEe (23.0%). The paternal line of cigocidad (61 subjects) obtained by comparing the frequency of gene Heiken and studying Rhesus boxes was 0.88 homozygote (DD) and 1.0 in hemicigotos (DD) with a value of Phi 0875. The correlation between paternal cigocidad based study of family and Rhesus boxes was 1.0 with a value of 1.0 Phi. The status of the couples in cigocidad both RhD negative women (cases) and positive (control) had an equal distribution of 0.611 and 0.612 respectively. Homozygote parents of 55.7% and 44.3% of hemicigotos. Cigocidad status of the children was statistically significant between the study groups (P<0.05). One limitation is that the study does not identify the molecular mechanisms of the condition RhD negative, only the mechanism of gene deletion, the principal individuals of Caucasian origin. The study of pseudogen RHDΨ not identified any cases in the study subjects and amplification of the RHD gene, which was presented in all 187 cases of RhD positive and 5 of the 41 subjects RhD negative, allowing reduce false positives in homozygous condition, whose molecular mechanism is the lack of hybrid box. Conclusions. Correlation was obtained between 1.0 and family study of the boxes in Rhesus as homo hemicigotos. The correlation between the study based on the frequency of the gene and Rhesus boxes was also 1.0 hemicigotos and fell to 0.88 homozygote.

RESUMEN: El estudio de la cigocidad RHD en las parejas de mujeres RhD negativo tiene importancia clínica para consejo genético pregestacional y gestacional en familias con historia de Enfermedad hemolítica del recién nacido. El objetivo fue identificar la condición de cigocidad del gen RHD en sujetos RhD positivo, por PCR-RFLP tradicional, y PCR en tiempo real en familias residentes en el Valle de México, así como determinar la concordancia de la cigocidad del gen RHD entre el fenotipo del sistema Rh y las pruebas moleculares.