Genetic analysis results and ultrasonographic markers in 41 fetuses with short femurs / 中华围产医学杂志

ABSTRACT

Objective:To analyze the genetic test results and ultrasonographic markers of 41 fetuses with short femurs and their relationship.Methods:This study retrospectively analyzed 41 fetuses who were diagnosed with short femurs by ultrasound during 19-37 gestational weeks and underwent prenatal genetic examination at the First Affiliated Hospital of Zhengzhou University from January 2018 to June 2019. According to the results of genetic examination, these cases were divided into three groups after excluding three cases of variants of unknown significance: genetically normal group, chromosome variation (including chromosomal aneuploidy and pathogenic or likely pathogenic copy number variations) group, and gene mutation (including pathogenic or likely pathogenic gene mutations) group. According to the head circumference (HC), abdominal circumference (AC) and femur length (FL), Z FL, FL/HC, FL/AC, &Delta;Z H-F and &Delta;Z H+A-2F for each fetus were calculated. One-way ANOVA and LSD- t test were used for statistical analysis. Results:(1) Among the 41 fetuses with short femurs, there were 28 in the genetically normal group, five in the chromosome variation group, three with chromosome variations of unknown significance and five in the gene mutation group. (2) In the genetically normal, chromosome variation and gene mutation groups, Z FL values were -2.78±0.77, -4.36±0.69 and -4.69±0.70; FL/HC ratios were 0.178±0.011, 0.170±0.010 and 0.131±0.022; FL/AC ratios were 0.197±0.013, 0.186±0.011 and 0.151±0.017; &Delta;Z H-F values were 2.49±1.09, 3.53±1.28 and 8.17±1.30; &Delta;Z H+A-2F values were 4.44±2.00, 6.78±2.20 and 14.28±1.26, respectively. The differences in Z FL values between the genetically normal group and the chromosome variation group as well as the gene mutation group were statistically significant (both P<0.05); so were the differences in FL/HC, FL/AC and &Delta;Z H-F values between the gene mutation group and the genetically normal group as well as the chromosome variation group (all P<0.05) and in any pairwise comparison of &Delta;Z H+A-2F among the three groups (all P<0.05). Conclusions:The genetic etiology of fetal short femurs is mainly related to chromosomal variations (including chromosomal aneuploidy and pathogenic or likely pathogenic copy number variations) and gene mutation. In fetuses with chromosome variation and gene mutation, the degree of the femoral development delay relative to the development of HC and AC is worse than that in the normal genetic results group.