A case of Aicardi-Goutières syndrome caused by TREX1 gene mutation

Aicardi-Goutières syndrome (AGS) is a rare genetic disorder involving the central nervous system and autoimmune abnormalities, leading to severe intellectual and physical disability with poor prognosis. AGS has a phenotype similar to intrauterine viral infection, which often leads to delays in genetic counseling. In this study, we report a case with a prenatal diagnosis of AGS. The first fetal ultrasound detected bilateral lateral ventricle cystic structures, and fetal MRI was performed to identify other signs. The right parietal lobe signal showed cerebral white matter abnormalities, and fetal brain development level was lower than that of normal fetuses of the same gestational age. Whole-exome sequencing revealed that the fetus carried the TREX1:NM_033629.6:exon2:c.294dup:p. C99Mfs*3 variant, suggesting that the c.294dup mutation of the TREX1 gene was the pathogenic mutation site, and the final comprehensive diagnosis was AGS1. In this article, we also reviewed the previous literature for possible phenotypes in the fetus and found that microcephaly and intrauterine growth retardation may be the first and most important markers of the intrauterine phenotype of AGS.

Clinical value of fetal facial profile markers during the first trimester

Objectives

To study the correlations between facial profile markers and crown-lump length (CRL) in a Chinese population, and to evaluate the clinical value of these markers for abnormal fetuses during the first trimester (11 to 13⁺⁶ gestational weeks). 

Methods

The facial profile markers were as followings: inferior facial angle (IFA), maxilla-nasion-mandible (MNM) angle, facial maxillary angle (FMA), frontal space (FS) distance and profile line (PL) distance. These markers were measured in facial mid-sagittal section through ViewPoint 6 software. The diagnostic value of these markers for abnormal fetuses was assessed by receiver operating characteristic (ROC) curves.

Results

According to the first-trimester scanning (FTS) and follow-up, 31 fetuses were enrolled in the abnormal group, including 14 cases of trisomy 21, 7 cases of trisomy 18, 10 cases with cleft lip and palate (CLP), and 1000 normal fetuses were selected. Among the normal fetuses, the IFA, FS distance and PL distance had negative correlations with CRL. The MNM angle and FMA had positive correlations with CRL. The mean IFA values for fetuses with trisomy 21 and trisomy 18 were 74.11° (standard deviation (SD) 7.48) and 69.88° (SD 7.08), respectively, which were significantly smaller than the normal fetuses (p = 0.013; p = 0.003). The mean MNM angle of fetuses with trisomy 18 and CLP were 6.98° (SD 2.61) and 9.41° (SD 2.57), respectively, which were significantly greater than the normal fetuses (p = 0.005; p < 0.001). The mean FMA values of trisomy 18 fetuses were 63.95° (SD 4.77), which was significantly smaller than the normal fetuses (p < 0.001). The mean FS distance of CLP fetuses was -0.22 mm (SD 1.38), which was significantly smaller than the normal fetuses (p < 0.001). The mean PL distance of trisomy 21, trisomy 18 and CLP fetuses were 2.89 mm (SD 0.41), 2.91 mm (SD 0.56) and 2.71 mm (SD 0.37), respectively. The difference with the normal fetuses had no statistical significance (p = 0.56; p = 0.607; p = 0.54).

Conclusions

Fetal facial profile markers had excellent correlations with CRL during the first trimester. IFA had certain clinical significance in detecting trisomy 21. FMA, IFA and MNM angle were reliable indicators for screening trisomy 18. The abnormal MNM angle and FS distance could be used as sensitive indicators for CLP. However, PL distance was not the best markers for trisomy 21, trisomy 18 and CLP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-05028-9.

Ultrasonographic study of fetal facial profile markers during the first trimester

Background

To establish reference ranges of fetal facial profile markers and study their correlations with crown-rump length (CRL) during the first trimester (11 ~ 13^+ 6 weeks’ gestation) in a Chinese population.

Methods

Ultrasonographic images of measuring fetal nuchal translucency (NT) were retrospectively selected randomly in normal fetuses whose parents were both Chinese. The facial markers included inferior facial angle (IFA), maxilla-nasion-mandible (MNM) angle, facial maxillary angle (FMA) and profile line (PL) distance. These markers were measured through ViewPoint 6 software by two experienced sonographers.

Results

Three hundred and eighty fetuses were selected. The ICCs (95 % CI) of intra-operator 1 reproducibility of IFA, MNM angle, FMA, PL distance were 0.944 (0.886 ~ 0.973), 0.804 (0.629 ~ 0.902), 0.834 (0.68 ~ 0.918) and 0.935 (0.868 ~ 0.969), respectively. The ICCs (95 % CI) of intra-operator 2 reproducibility of IFA, MNM angle, FMA, PL distance were 0.931 (0.857 ~ 0.967), 0.809 (0.637 ~ 0.904), 0.786 (0.600 ~ 0.892) and 0.906 (0.813 ~ 0.954), respectively. The ICCs (95 % CI) of inter-operator reproducibility of IFA, MNM angle, FMA, PL distance were 0.885 (0.663 ~ 0.953), 0.829 (0.672 ~ 0.915), 0.77 (0.511 ~ 0.891) and 0.844 (0.68 ~ 0.925), respectively. The average ± SD of IFA, MNM angle, FMA and PL distance were 80.2°±7.25°, 4.17°±1.19°, 75.36°±5.31°, 2.78 ± 0.54 mm, respectively. IFA and PL distance significantly decreased with CRL, while MNM angle and FMA significantly increased with CRL.

Conclusions

It was feasible to measure fetal facial markers during the first trimester. In Chinese population, the reference ranges of IFA, MNM angle, FMA and PL distance were 80.2°±7.25°, 4.17°±1.19°, 75.36°±5.31°, 2.78 ± 0.54 mm, respectively, and the measurements were found to correlate with CRL.