Outcome of non-visualization of fetal gallbladder on second-trimester ultrasound: cohort study and systematic review of literature

OBJECTIVES

To investigate the ultrasound characteristics and outcome of fetuses with non-visualization of the fetal gallbladder (NVFGB) followed in our tertiary university hospital, and to provide a comprehensive review of the literature on prenatal findings and outcome of NVFGB.

METHODS

NVFGB was defined as non-visualization of the gallbladder on two targeted ultrasound examinations performed within a 1-week period. First, we reviewed the medical records of NVFGB cases managed in our center over a 9-year period. Then, we performed a systematic review of the literature to identify studies on NVFGB. The incidence of chromosomal anomalies, later visualization of the gallbladder, gallbladder agenesis, cystic fibrosis and biliary atresia was assessed in fetuses with isolated and non-isolated NVFGB. The role of hepatic enzyme measurements in the diagnosis of cystic fibrosis and biliary atresia in fetuses with NVFGB was also reviewed.

RESULTS

Sixteen cases of NVFGB were followed in our center, in 10 (62.5%) of which it was an isolated finding. The incidence of biliary atresia was 12.5% and that of gallbladder agenesis was 12.5%, while no case of cystic fibrosis was reported. The gallbladder was visualized later in pregnancy or postnatally in 43.8% and 25.0% of cases, respectively. A total of seven studies, including our cohort, involving a total of 280 NVFGB cases, met the inclusion criteria for the systematic review. Overall, 20.5% of fetuses had an associated ultrasound anomaly, and the incidence of chromosomal anomaly in this group was 20.4%. In cases with isolated NVFGB, the incidence of chromosomal anomaly was 1.9%. In fetuses with normal karyotype and isolated NVFGB, the gallbladder was later visualized in 70.4% of cases, while the incidence of gallbladder agenesis, cystic fibrosis and biliary atresia was 25.2%, 3.1% and 4.8%, respectively. In fetuses with non-isolated NVFGB, the incidence of cystic fibrosis and biliary atresia was 23.1% and 18.2%, respectively. The negative predictive value of amniotic fluid enzyme levels for the prediction of severe disease (including biliary atresia or cystic fibrosis) ranged between 94% and 100% when evaluated before 22 weeks' gestation, and dropped to 88% after 22 weeks.

CONCLUSIONS

In cases with persistent NVFGB, the risk of a severe postnatal condition should be considered. A detailed ultrasound scan should be offered and parents tested for cystic fibrosis gene mutation. An invasive procedure for karyotyping and measurement of liver enzyme concentrations before 22 weeks constitutes a reasonable work-up. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

P601Heart disease and pancreatic iron in thalassemia major

Background

Some preliminary data have postulated a correlation between pancreatic iron overload and heart iron and function in thalassemia major (TM) patients.

Purpose

In the present multicenter study we explored systematically the link between pancreatic iron and heart disease in a large cohort of TM patients.

Methods

We considered 880 TM patients (467 M, mean age 37.83±10.05 years) enrolled in the E-MIOT (Extension-Myocardial Iron Overload in Thalassemia) project. T2* measurements were performed over pancreatic head, body and tail and global value was the mean. Myocardial iron overload (MIO) was quantified using a T2* segmental approach. Biventricular function parameters were assessed by cine images. Late gadolinium enhancement (LGE) images were acquired to detect myocardial fibrosis.

Results

A significant correlation between pancreatic and cardiac iron was reconfirmed in this more numerous population and a normal pancreas T2* showed negative predictive value of 100% for cardiac iron.

LGE sequences were acquired in 273 TM patients and 84 (30.77%) of them showed macroscopic myocardial fibrosis. Global pancreas T2* values were significantly lower in patients with fibrosis (7.38±6.19 ms vs 11.91±9.79 ms; P<0.0001).

Sixty-four patients had at least one cardiac complication (arrhythmias, heart failure, pulmonary hyperthension, vascular disease). Patients with cardiac complications showed a significant lower global pancreas T2* (7.83±5.61 ms vs 12.76±10.34 ms; P=0.024). Specifically, global pancreas T2* values were significantly lower in patients with heart failure as well as in patients with arrhythmias and all patients with one of these two diseases had a pathologic global pancreas T2* value (see Figure).

Conclusion

Pancreatic iron is a strong predictor not only for cardiac iron, but also for cardiac complications supporting a more profound link between pancreatic iron and heart disease in TM.

HFE gene mutations an Apulian population: allele frequencies

Hereditary hemochromatosis (HH) is an autosomal recessive trait regarding iron metabolism frequently found in Caucasian populations. The C282Y mutation of the HFE gene, held responsible for HH, has been identified as the major genetic basis for the phenotypic expression of HH whereas two additional mutations of the HFE H63D and S65C gene appear to be associated with a milder form of HH. A high allele frequency of C282Y and H63D has been reported in Northern European populations. In Italy, the overall allele frequency was 0.5% for the C282Y mutation, 12.6% for the H63D mutation and 1.1% for the S65C mutation. In this study, we evaluated the allele frequency of the three principal HFE mutations (C282Y, H63D, S65C) together with eight additional mutations (V53M, H63H, Q127H, E168Q, E168stop, W169stop, V59M, Q238P) in 500 healthy Apulian subjects. No subject homozygous for the C282Y mutation was found while 3% of subjects were heterozygous for this mutation. Heterozygosity and homozygosity for the H63D mutation were 26 and 1%, respectively. Only five subjects were heterozygous for the S65C mutation. Overall, the allele frequency was 1.5% for C282Y, 14% for H63D, 0.5% for S65C and 0% for the other mutations. The transferrin saturation (TS) was significantly higher in subjects heterozygous for the H63D mutations with respect to subjects with a normal genotype, though all were within the normal range. No statistically significant difference in the allele frequency was noted in the Apulian population compared to that in Northern and Southern Italy.

Analysis of HLA-DRB1*-A* and -B* alleles in prenatal diagnosis for determination of maternal contamination in fetal DNA

During chorionic villi sampling for prenatal diagnosis with molecular biology techniques, contamination by maternal decidua frequently occurs and can lead to misinterpretation of the test results. To avoid such problems, we present a new method for appraising maternal contamination of fetal DNA, based on genomic typing of the highly variable human leukocyte antigen (HLA) locus-DRB1*, locus A* and locus B* regions by genetic amplification with sequence-specific primers and PCR. Fetal DNA samples obtained for beta-thalassemia diagnosis were analysed after artificial contamination with increasing maternal DNA concentrations ranging from 0.5 to 10% (0.5, 1, 3, 5 and 10%). The approach was found to be rapid, specific, reproducible and highly sensitive and permits recognition of 1-3% contamination by maternal DNA concentrations. The system currently used for detecting maternal DNA contamination in fetal samples is the analysis of polymorphic loci by variable number of tandem repeats and/or short tandem repeats. We propose that the analysis of HLA alleles may provide a valid alternative or complement to this system.

Genotype and phenotype correlation in glucose-6-phosphate dehydrogenase deficiency

BACKGROUND AND OBJECTIVES

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common erythrocytic enzymatic disorder in Italy and is characterized by wide clinical, biochemical and molecular variability. We studied the clinical and hematologic data from 54 G6PD-deficient, unrelated males from the Apulia region.

DESIGN AND METHODS

Analyses for enzymatic activity, G6PD electrophoresis and molecular typing were performed on all subjects. Thirty-nine subjects (72.2%) showed a severe G6PD deficiency (<10% residual enzymatic activity) and 15 subjects (27.8%) a moderate deficiency (10--60% residual activity).

RESULTS

The Mediterranean variant was found in 48.2% of cases, the Seattle variant in 33.3%, the A- variant in 7.45% and the Montalbano variant in 3.7%; the variant was not identified in four subjects. Thirty-two patients (59.2%) were asymptomatic; of these, 37.04% demonstrated acute hemolytic crises induced mainly by ingestion of fava beans and 3.7% had had neonatal jaundice. Acute hemolytic anemia was found in 53.8% of subjects with the Mediterranean variant, in 5.5% with the Seattle variant, in 100% with the A-variant and 0% with the Montalbano variant.

INTERPRETATION AND CONCLUSIONS

Enzymatic activity was shown to be a poor predictive parameter of acute hemolytic crises and was not correlated with clinical features. Subjects with Mediterranean or A- variants had a more severe clinical phenotype which was not related to enzymatic activity. The Seattle, and probably the Montalbano, variant appears to have a milder clinical expression.

Lymphocyte subset reconstitution after HLA-identical placental blood transplantation (PBT) or PBT plus bone marrow transplantation (BMT) in three children with beta-thalassemia major

The kinetics of circulating lymphoid cells were evaluated in three children suffering from beta-thalassemia major after HLA-identical sibling placental blood transplant (PBT) in one patient and placental blood plus bone marrow transplantation (BMT) in two patients. Recovery of the main lymphocyte subsets, as determined by phenotype analysis of circulating PBMCs, was complete within 2 months after transplant. NK (CD56+) cells were the first to appear in peripheral blood, followed by T (CD3+, CD2+, CD7+) and B (CD19+) cells. Of the T lymphocytes, the CD8+ were the first to reconstitute, but recovery of CD4+ cells was also rapid and within 6 months these T cells reached normal values. The expression of CD57 by NK or T cells was slightly delayed. The evaluation of RA and RO isoform expression of the CD45 molecule showed a prevalence of the CD45RA antigen with a ratio of 2-3:1. In the PBT only patient, T cells expressing the CD45RO antigen prevailed in the early post-transplant period. Severe or chronic GVHD was not observed. This experience demonstrates that reconstitution of lymphocyte subsets is successful in genetic hematological diseases after transplantation of HLA-identical placental blood or placental blood plus bone marrow from healthy or heterozygous siblings. Bone Marrow Transplantation (2000) 26, 743-747.

Prenatal diagnosis of beta-thalassaemia using fetal erythroblasts enriched from maternal blood by a novel gradient

We have assessed a new technique for the isolation of fetal erythroblasts from maternal blood for the non-invasive prenatal diagnosis of pregnancies at risk of beta-thalassaemia. This method relies on the separation of erythroblasts from maternal nucleated cells by a novel step gradient and high speed centrifugation. In four of the six cases examined, single erythroblasts were identified by immunohistochemistry for zeta (zeta) globin. These were individually micromanipulated and analysed by single cell polymerase chain reaction (PCR) and subsequent sequencing of the region of beta-globin locus where the mutations most common to the region of Puglia, Italy, are clustered. In each of the four instances where fetal erythroblasts were identified by antibody staining, the fetal beta-globin genotype was correctly determined. To date, this represents the largest series of non-invasive prenatal diagnoses performed for this haemoglobinopathy.

Promoter mutations producing mild beta-thalassaemia in the Italian population

In this study we have investigated the molecular basis for a mild form of beta-thalassaemia in three patients of Italian descent. In two, belonging to different families and affected by a mild and late-presenting form of thalassaemia major, direct sequencing of amplified DNA detected a C----T substitution at position -87 of the beta-globin gene in the compound heterozygous state either with codon 39 nonsense mutation or beta +IVSI, nt 110 mutation. The -87 (C----T) mutation has been previously described, in combination with the beta +IVSI, nt 110 mutation, in a single patient with thalassaemia intermedia. Both our patients showed a more severe phenotype as compared to that resulting from compound heterozygosity for a severe beta-thalassaemia mutation and another promoter mutation (-87, C----G) at the same position. In the third patient with the thalassaemia intermedia phenotype, we detected a novel promoter mutation, consisting in a C----A substitution at position -86, in combination with the codon 39 nonsense mutation. The results of this study indicate that different nucleotide substitutions affecting the proximal CACCC box of the beta-globin gene in combination with severe beta-thalassaemia, produce a mild form of thalassaemia ranging in severity from thalassaemia intermedia to late-presenting thalassaemia major.

Molecular basis of beta-thalassemia intermedia in a southern Italian region (Puglia)

We investigated the molecular bases for a mild phenotype by alpha-, beta- and gamma-globin gene analyses in 22 patients with transfusion-independent thalassemia intermedia (15) or a late-presenting form of thalassemia major (7) originating from Puglia, a region of southern Italy. Twenty-two patients with thalassemia major served as controls. The beta+ IVS-I nt 6 of the beta-globin gene and the C----T substitution at position -158 5' of the G gamma-globin gene were detected more frequently in patients with thalassemia intermedia or late-presenting thalassemia major considered together as compared to those affected by typical transfusion-dependent thalassemia major. Three of 15 patients with thalassemia intermedia had the triple alpha-globin gene arrangement in the heterozygous (2) or homozygous state (1) in association with heterozygous beta zero-thalassemia. From these results, we may conclude that the inheritance of a mild beta-thalassemia allele such as the beta+ IVS-I nt 6 mutation, in the homozygous or heterozygous state, the coinheritance with homozygous beta zero-thalassemia of the -158 (C----T) G gamma gene promoter mutation and the presence of heterozygous beta-thalassemia/triple alpha-globin gene arrangement are the most common reasons accounting for the development of attenuated forms of beta-thalassemia in Puglia.