Fetal cholecystomegaly: a prenatal marker of aneuploidy

Prenatal detection and molecular cytogenetic characterization of Xp deletion and Xq duplication: a case report and literature review

BACKGROUND

Copy number variation (CNV) of X chromosome can lead to a variety of neonatal abnormalities, especially for male fetuses. In recent years, due to the high sensitivity and high specificity of NIPS, its application has gradually expanded from chromosome aneuploidy to CNV. Few prenatal cases involving the detection of Xq duplication and deletion by NIPS have been reported, but it is of great significance for genetic counseling.

CASE PRESENTATION

A 36-year-old woman was referred for prenatal diagnosis and genetic counseling at 17 weeks of gestation because of abnormal result of noninvasive prenatal screening (NIPS). Multiple congenital malformations, hydrocephalus, and enlarged gallbladder were observed by prenatal ultrasound. Amniocentesis revealed the karyotype of the fetus as 46, XN, add(X) (p22.2) and the result of chromosomal microarray analysis was arr[hg19] Xq27.1q28(138,506,454-154896094) × 2 and arr[hg19] Xp22.33p22.32(168,551-5,616,964) × 1. CNV-seq showed that the mother shares a 16.42 Mb duplication in the Xq27.1-q28 region and a 2.97 Mb deletion in the Xp22.33-p22.32 region. After genetic counseling, the couple chose to terminate the pregnancy.

CONCLUSION

The combination of NIPS and CMA would be of values in detection of subchromosomal duplications and/or deletions at fetal stage. The detection of X chromosome aberration in a male fetus should give suspicion of the possibility of maternal inheritance.

Improving prenatal detection of abdominal supraumbilical anomalies: The sonographic examination of fetal anechoic spaces of upper abdomen revisited

Visualization of the axial plane of the fetal abdomen is mandatory to obtain abdominal biometry in the assessment of fetal growth in the second and third trimesters. The main anatomic landmarks that must be identified in this view include the fetal stomach and the intrahepatic portion of the umbilical vein, which are easily identifiable as they appear anechoic on ultrasound. The gallbladder is the other prominent anechoic structure in this plane. Focused study of the morphological characteristics of, and spatial relationship among, these three anechoic spaces is a simple technique to detect anomalies involving fetal upper abdominal organs. In this review, the sonographic features of those conditions that can be detected using this technique, which was termed the Fetal Examination of the Anechoic Spaces of upper abdomen Technique (FEAST), are classified and illustrated.

Prenatal diagnosis with chromosome microarray and pregnancy outcomes of fetuses with biliary tract system abnormalities

OBJECTIVES

To investigate the prenatal diagnostic value of chromosome microarray analysis (CMA) in fetuses presenting with ultrasound-based biliary tract system (BTS) anomalies.

METHODS

Amniocentesis was performed and CMA was applied in 271 pregnant women carrying fetuses with BTS abnormalities between April 2015 and December 2020. Pregnancy outcomes and fetal prognosis were followed from 1 to 6 years.

RESULTS

Sixteen cases (5.9%, 16/271) of chromosomal anomalies were detected. The detection rate of chromosomal abnormalities was significantly higher for fetuses with nonisolated BTS anomalies than for those with isolated BTS anomalies (9.0% vs 0%, p=0.0017). Follow-up results were obtained from 267 fetuses, including 25 cases of termination of pregnancy (9.4%), 237 live births (88.8%) and 5 (1.9%) neonatal demises. The incidence of congenital biliary atresia in the small gallbladder and nonvisualized gallbladder groups were 3.0% (1/33) and 9.5% (7/74), respectively; however, none was detected on postnatal ultrasound reexamination in the gallbladder enlargement or the other BTS groups.

CONCLUSIONS

An isolated BTS abnormality is not an indication for invasive prenatal chromosomal analysis. When combined with other ultrasonographic abnormalities, prenatal CMA should be provided. When a small or non-visualized gallbladder is found prenatally, ultrasonography is limited in the differential diagnosis of congenital biliary atresia. This article is protected by copyright. All rights reserved.

[Prenatal diagnosis of gallbladder abnormalities: a review]

OBJECTIVES

Our objective was to review the possible consequences and management possibilities of fetal gallbladder abnormalities.

MEANS AND METHODS

A search through publications was conducted using the Pubmed database.

RESULT

The majority of fetal gallbladder abnormalities are benign (absence, malformation, cholelithiasis, sludge...). When the absence of gallbladder is isolated, biliary tract atresia, that is a rare but severe disease, must be evoked.

CONCLUSION

An extensive morphological analysis of the fetus is required in cases with gallbladder abnormalities. An amniocentesis for caryotype analysis must be proposed when an absent gallbladder is associated with other fetal abnormalities and in all cases of absent gallbladder for digestive enzymes evaluation to rule out a biliary atresia.

Prenatal diagnosis of liver and biliary tract disease

The diagnosis and detection of some forms of liver and bile duct disease have become possible since the adoption of routine fetal ultrasound scanning in the UK, and the remarkable advances in molecular biological techniques. Nevertheless, although antenatal detection may well have improved, it remains difficult to offer a specific diagnosis, much less a prognosis, in most cases. Cystic dilatation of the biliary tree is probably the most common finding. This may be due to cystic choledochal malformations or, occasionally but crucially, biliary atresia. Postnatal investigations (such as ultrasonography, magnetic resonance cholangiography and liver histology) must take the latter possibility into account, as early surgery is the key to a successful outcome following reconstructive biliary surgery. Antenatally diagnosed liver tumours are usually of vascular origin and have an unpredictable natural history. Some may cause fetal cardiac failure and are candidates for in-utero intervention, but in all likelihood, a large proportion will resolve without specific therapy.

Nonvisualization of the fetal gallbladder in early pregnancy: comparison with clinical outcome

PURPOSE

To prospectively assess the frequency of a nonvisualized fetal gallbladder in early pregnancy and to determine its prognostic value.

MATERIALS AND METHODS

Fetal transvaginal ultrasonography (US) was performed in 29,749 consecutive pregnant women at 14-16 weeks gestation. A nonvisualized fetal gallbladder was defined if the gallbladder could not be depicted during two targeted examinations within 1 week. In such cases, women were offered an amniocentesis for fetal karyotype and hepatic enzyme analysis. Repeat transabdominal fetal US was performed at 22-26 weeks' gestation. If the gallbladder was still not depicted, US was performed postnatally.

RESULTS

The gallbladder was not visualized in early pregnancy in 34 fetuses (0.1%; incidence of one in 875 pregnancies). Associated structural malformations were detected in 14 of 34 (41%) fetuses, five of which also had an abnormal karyotype. Pregnancy was terminated in nine of these 14 fetuses. In the remaining five patients who continued pregnancy, the gallbladder was detected later in pregnancy in four. However, only one infant was healthy. Nonvisualization of the gallbladder as an isolated finding was noted in 20 of 34 (59%) fetuses, all of which had a normal outcome. The gallbladder was detected later in pregnancy in 11 of these fetuses and after birth in two neonates, while no gallbladder was detected after delivery in five other neonates. Two patients were lost to follow-up.

CONCLUSION

Nonvisualization of the fetal gallbladder in early pregnancy is uncommon but associated in many cases with other fetal anomalies.

Ultrasound screening for fetal chromosome anomalies

Ultrasound evidence for aneuploidy may be found in almost every organ of the fetus and can be used to modify the risk of aneuploidy. The diagnosis of these minor anomalies on second-trimester ultrasonography will increase the risk of an abnormal karyotype whereas the absence of these findings may reduce this danger. The most specific and most ominous isolated markers for fetal aneuploidy are nuchal findings (edema or cysts), indicating the need to obtain a fetal karyotype in all cases irrespective of maternal age or results of biochemical serum screening. Hyperechoic fetal bowel is apparently also a strong indicator of fetal aneuploidy. Other isolated sonographic markers may increase the risk of an abnormal karyotype three- to ninefold. Most sonographic markers for aneuploidy specify an increased risk for Down syndrome, but choroid plexus cysts are apparently more specific for trisomy 18. Along with other screening methods, ultrasound screening for fetal aneuploidy should be used routinely to identify additional pregnancies at need for evaluation of fetal karyotype.

Sludge in fetal gallbladder: natural history and neonatal outcome

Normal and pathological conditions of the fetal gallbladder have been a subject of recent investigation by ultrasonographers. Fetal gallstones are the most common abnormal finding and appear as echogenic foci within the gallbladder. We report a series of five fetuses in whom the gallbladders were filled with sludge which appeared as a pear shape echogenic structure. In the majority of cases, gallbladder sludge mimicked intrahepatic calcification or echogenic bowel. Serial ultrasound examinations of these fetuses revealed good interval growth. The gallbladders remained echogenic and were normal in size in three cases and were moderately enlarged in two. All neonates were born in normal condition with no identifiable malformations. Follow-up was obtained in four infants using abdominal ultrasound. A normal appearing sludge free gallbladder was seen in three neonates at 6 weeks of life and in four infants at 12 weeks. Accurate diagnosis of gallbladder sludge will spare the patient unnecessary work-up and anxiety. The natural history of gallbladder sludge in the fetus is benign in nature and is similar to that of fetal gallstones.