Prenatal Diagnosis of Cystic Fibrosis: Ultrasonography of the Gallbladder at 17–19 Weeks of Gestation

Abstract

We have investigated the ultrasonographic signs that can help in the prenatal diagnosis of cystic fibrosis in 197 risk fetuses and compared them with 353 control fetuses. In 60 fetuses with a 1:4 risk for the disease, the gallbladder was also examined. All ultrasonograms were performed just before amniocentesis at 17–19 weeks of gestation. A previously described intra-abdominal hyperechogenic mass was found in 73% of the 48 affected fetuses, but 32 of the 149 unaffected fetuses also had this feature, giving a specificity of 77% and a sensitivity of 78%. When we investigated the gallbladder, we found 9 of the 12 affected fetuses to be without evidence of a gallbladder during the sonographic examination (none of the healthy or control fetuses had such a feature), giving a positive predictive value of 100%, a specificity of 100% and a sensivity of 75%. The combined presence of an abnormal gallbladder and a hyperechogenic intra-abdominal mass yields the same positive predictive value and specificity, but does not improve the accuracy. Ultrasonography appears to be a good additional diagnostic tool for the prenatal diagnosis of cystic fibrosis, especially when the enzyme activities disagree. Furthermore, these results lead us to think that such a finding during routine ultrasonographic examination at 17–29 weeks could be a means of screening for cystic fibrosis. The absence of the gallbladder during the sonographic examination of fetuses at risk for cystic fibrosis at 17–19 weeks of gestation can help in the prenatal detection of the disease.

CFTR, Mucins, and Mucus Obstruction in Cystic Fibrosis

“…1C). This is supported by ultrasound studies in the gastrointestinal tract, wherein 90% of CF fetuses manifest inspissated meconium in their distal ileum during the 17 -19-wk gestation period (Duchatel et al 1993). Although this is generally reabsorbed, a small percentage of CF infants present with mucin-containing meconium ileus at birth (Schachter and Dixon 1965).…”

“…Meconium ileus and intestinal mucus-based obstruction are among the earliest manifestations of CF (Duchatel et al 1993) and may reflect a failure in utero to proteolytically digest swallowed and sloughed proteins, which may include mucins. Distal intestinal mucus-based obstruction occurs in .20% of adult patients.…”

Nonvisualization of the fetal gallbladder by second‐trimester ultrasound scan: strategy of clinical management based on four examples

“…When nonvisualization of the gallbladder is confirmed by a second US examination performed 7 to 15 days later, the etiology should be investigated because of the association with various abnormalities, such as renal agenesis, hydronephrosis, cerebral ventricular dilatation, chromosomal anomalies (particularly trisomy 21), cystic fibrosis, biliary atresia, and multiple malformation (Bennion et al, 1988;Bronshtein et al, 1993;Duchatel et al, 1993;Albayram et al, 2002;Ben-Ami et al, 2002;Simon-Bouy et al, 2002;Blazer et al, 2002;Ochshorn et al, 2007). However, the absence of indications in the US does not exclude severe abnormalities, such as cystic fibrosis or biliary duct atresia.…”

“…However, the absence of indications in the US does not exclude severe abnormalities, such as cystic fibrosis or biliary duct atresia. In cystic fibrosis, nonvisualization of the gallbladder may be isolated or associated with bowel dilatation, or hyperechogenic fetal bowel, ascites, or meconium peritonitis (Duchatel et al, 1993;Blazer et al, 2002). Biliary atresia is either syndromic (10% of cases), and if so associated with anomalies (intestinal malrotation, situs inversus, malposition of the spleen, cardiac defect), or nonsyndromic (Chardot, 2006).…”

Respiratory Tract Mucin Genes and Mucin Glycoproteins in Health and Disease

“…Evidence for a fundamental mucus abnormality in CF is supported by ultrasound studies, wherein 90% of CF fetuses during the 17-to 19-wk period of gestation manifest inspissated meconium in the distal ileum, which is generally reabsorbed by birth (68). Gastrointestinal mucus obstruction is not life threatening except to the small number of CF infants born with meconium ileus.…”