Análisis clínico-epidemiológico de las niñas recién nacidas con síndrome de Turner y de aquellas con tres cromosomas X

Abstract

As far as we know, this article represents the fi rst epidemiological analysis of two series of consecutive newborn infants who presented with monosomy X or three X chromosomes, using data from ECEMC’s case-control study. For this analysis, four groups of newborn girls were used: infants with 45,X, those with 47,XXX, all other newborn females with congenital defects, and the group of female controls. Two types of comparative analyses between those groups were performed: the fi rst includes the study of anthropometric variables at birth, and of the maternal and paternal ages; the second approach analyzes the relative frequency of each congenital defect in the two groups of girls with 45,X, and 47,XXX. To do this, we divided the frequency of each defect observed in newborn females with 45,X and 47,XXX, by the corresponding frequency observed in the group formed by the females with other birth defects. The value of this quotient for each anomaly, offers the times each defect is more (or less) frequent among the girls with each chromosomal alteration than in the group of newborn girls with other defects. Results from the fi rst group of analyses: These showed signifi cant differences for: a lower birth weight in 45,X infants (Table 2), who only differ in the gestational age (Table 4) from the group of control females, having an OFC lower than that of the two reference groups (Table 4). However, regarding the newborn length (Table 5) of both 45,X and 47,XXX infants, it was lower than among the two reference groups. Finally, regarding the analyses of the parental ages (Tables 6,7), the differences are established in relation with a statistically significant higher maternal age in infants having three X chromosomes than the other three groups. Moreover, the analyses of the mean parental ages differences (Table 8), suggest that the extra X chromosome in infants with 47,XXX, is of maternal origin. Results from the second group of analyses: The clinical analyses showed that newborns with 45,X have many more congenital defects than the group presenting with three X chromosomes. In addition, this approach depicts those defects that are signifi cantly more frequent (expressed as the number of times they are more frequent) in each of the two series of infant girls with 47,XXX and 45,X (Tables 9 and 10, respectively) than in the group constituted by the rest of newborn girls (within the same period of time and hospitals). Moreover, it is also shown that other birth defects have the same frequency in the three groups of girls with congenital anomalies, which suggests that they may not be related with the chromosomal abnormality, but attributable to the population risk. Conclusions: With consecutive series of newborn infants with congenital defects, we can structure series of cases with the same type of cause. This is highly valuable since this allows us to defi ne both the spectrum of birth defects for each cause and the type of defects that are specifi cally associated with the cause. This information is of enormous importance either for prenatal diagnosis, or for a correct diagnosis and prognosis, including the anticipatory guidance.