Evaluation of birth weight in patient with various karyotypes of sex chromosome abnormality

Objective: There have been many reports stating that individuals with an X chromosome aberration have a tendency to intrauterine growth retardation, but there has been only one report describing fetal growth in each karyotype of X chromosome aberration. We therefore investigated the relationship between each karyotype of sex chromosome aberrations and intrauterine growth retardation. Methods: We analyzed birth weight and body height at the first visit in 41 individuals with an X chromosome aberration karyotype (mosaicism or non-mosaicism of X monosomy, deletion, addition, isochromosome, ring chromosome, and marker chromosome of sex chromosome). Results: Out of 41 subjects, short stature after birth was observed in 40 cases (97.6%). The incidence of SGA (small for gestational age) (39.0%; 16 of 41 cases) was higher than that in the general population. Futhermore, the incidence of SGA was different by karyotype; the highest incidence (66.7%) was found in 45,X/46,X,i(Xq) and 45,X/46,X,r(X) groups, and the lowest incidence (14.3%) was found in 45,X/46,XX groups. Conclusions: Individuals with an X chromosome aberration have a tendency to fetal growth retardation. Since the incidence of growth retardation differed according to the karyotype aberration, it is postulated that a gene responsible for fetal growth may be located on the distal short arm of the X chromosome, especially p22.