RESUMO
The results of a retrospective analysis of newborn population with neural tube defects (NTD) occurred in the Hospital Pedro Garcia Clara at Zulia State for the period 1982-1988, sex, birth condition, maternal age, number of pregnancies and mother's mean permanency of time in the zone, were studied. The control sample were children who were born the same day and of the same sex as the malformed children. By that period, the NTDs occupied the first place as morbidity caused for congenital malformations. NTDs had an incidence rate of 2.28 out of thousand total of births and can be considered one of the highest reported in the country. The major rate, 5.5 per 1000 was observed in 1986. The frequency of NTDs was higher in stillbirths and females. There were no differences between NTDs and controls in relation with maternal age and number of pregnancies in the mother. There was a heterogeneous geographical distribution with high concentration of cases of NTDs in Bachaquero and Mene Grande. The permanency of the NTDs's mothers was greater than that the controls' mothers. According to this investigation, it is suggested a necessity for more profound studies in order to identify and clarify some possible environmental conditions that could explain the present findings.
Assuntos
Defeitos do Tubo Neural/epidemiologia , Feminino , Hospitais , Humanos , Recém-Nascido , Masculino , Venezuela/epidemiologiaRESUMO
The aim of this work is to reevaluate the hypothesis of the existence of a possible genetic control of nondisjunction of chromosome 21. The population under study was the families trisomy (TLI) as diagnosed in the Medical Genetic Unit of LUZ from 1971 to 1988. The control population was the families of 418 individuals with no apparent genetic pathology (CON), approximately matched in age with the patients. The frequency of consanguineous unions in parents (UCPM), maternal grandparents (UCAM) and paternal grandparents (UCAP) of both patients and controls was determined. The results indicated that UCPM was significantly greater in TLI than CON while the UCAM and UCAP were more frequent in CON. The coefficient of consanguinity in parents of TLI was three times greater than in parents of CON. The results of this investigation suggest that the consanguinity should be considered another risk factor for the nondisjunction of chromosome 21 and it is independent of maternal age and support the hypothesis that there exists an autosomal recessive gene that, in the homologous state, results in a predisposition toward nondisjunction of chromosome 21 in the first mitotic division.