Search

First trimester ultrasound screening is an essential fetal examination performed generally at 11-13 weeks of gestation (WG). However, it does not allow for an accurate description of all fetal organs, partly due to their development in progress. Meanwhile, increased nuchal translucency (INT) is a widely used marker known to be associated with chromosomal deleterious rearrangements. We report on a 14 WG fetus with an association of INT and univentricular congenital heart malformation (CHM) leading to chorionic villous sampling (CVS). Cytogenetic investigations performed using array-Comparative Genomic Hybridization (CGH) and fluorescence in situ hybridization (FISH) demonstrated a 1.17 Mb deletion in 16q24.1 encompassing FOXF1 arisen de novo on maternal inherited chromosome. Fetopathological study confirmed CHM with hypoplastic left heart syndrome (HLHS) associating aortic atresia, mitral stenosis, and left ventricular hypoplasia and revealed in addition specific lung lesions corresponding to alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV). This is so far the first case of first trimester prenatal diagnosis of ACDMPV due to the deletion of FOXF1 gene. An interpretation of the complex genomic data generated by ultrasound markers is facilitated considerably by the genotype-phenotype correlations on fetopathological examination.

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a rare lethal lung developmental disease. Affected infants manifest with severe respiratory distress and refractory pulmonary hypertension and uniformly die in the first month of life. Heterozygous point mutations or copy-number variant deletions involving FOXF1 and/or its upstream lung-specific enhancer on 16q24.1 have been identified in the vast majority of ACDMPV patients. We have previously described two unrelated families with a de novo pathogenic frameshift variant c.691_698del (p.Ala231Argfs*61) in the exon 1 of FOXF1. Here, we present a third unrelated ACDMPV family with the same de novo variant and propose that a direct tandem repeat of eight consecutive nucleotides GCGGCGGC within the ~ 4 kb CpG island in FOXF1 exon 1 is a novel mutation hotspot causative for ACDMPV.

Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACDMPV) is a rare, autosomal dominant disorder of interstitial lung development, leading to pulmonary hypertension, and death in infancy. Associated features include malformations of the heart, gastrointestinal tract, and genitourinary system. ACDMPV is caused by heterozygous variants in the FOXF1 gene or microdeletions involving FOXF1. We present a male infant with ACDMPV, hypoplastic left heart sequence (HLHS), duodenal atresia, and imperforate anus due to a de novo, in frame deletion in FOXF1: c.209_214del (p.Thr70_Leu71del). Previous reports have suggested that microdeletions involving FOXF1 are associated with ACDMPV with congenital heart defects, including HLHS, gastrointestinal atresias, and other anomalies; whereas likely pathogenic variants within FOXF1 have not been reported with ACDMPV and HLHS. This is the first patient reported with ACDMPV, HLHS, imperforate anus, and duodenal atresia associated with a likely pathogenic variant in the FOXF1 gene.

Position effects due to disruption of distant cis-regulatory regions have been reported for over 40 human gene loci; however, the underlying mechanisms of long-range gene regulation remain largely unknown. We report on two patients with alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) caused by overlapping genomic deletions that included a distant FOXF1 transcriptional enhancer mapping 0.3 Mb upstream to FOXF1 on 16q24.1. In one patient with atypical late-onset ACDMPV, a ∼1.5 Mb deletion removed the proximal 43% of this enhancer, leaving the lung-specific long non-coding RNA (lncRNA) gene LINC01081 intact. In the second patient with severe neonatal-onset ACDMPV, an overlapping ∼194 kb deletion disrupted LINC01081. Both deletions arose de novo on maternal copy of the chromosome 16, supporting the notion that FOXF1 is paternally imprinted in the human lungs. RNAi-mediated knock-down of LINC01081 in normal fetal lung fibroblasts showed that this lncRNA positively regulates FOXF1 transcript level, further indicating that decrease in LINC01081 expression can contribute to development of ACDMPV.

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a congenital malformation that leads to severe pulmonary hypertension and respiratory failure. It has been associated with deletion of, or mutation in, FOXF1 on 16q24.1, a gene encoding a forkhead transcription factor expressed in the mesenchyme of the developing lung. Here we report on the identification of a pericentric inversion on chromosome 16 (p11.2q24.1) in a case of lethal ACDMPV with atrioventricular septal defect and duodenal atresia. Array-CGH indicated that the inversion is balanced, and FISH showed that the q-arm breakpoint occurs 134 ± 10 kb upstream (5'; centromeric) of FOXF1. This is suggestive of cis-regulatory elements located more than 130 kb 5' of FOXF1, and analysis of genome-wide data sets of chromatin modifications in two different cell types suggested that the FOXF1 regulatory domain covers more than 300 kb, and perhaps up to 433 kb, upstream of the gene, but only 3 kb downstream. The 588 kb gene-free region between FOXF1 and the next gene in the centromeric direction, IRF8, is highly conserved between species and divided into two distinct regulatory domains by an insulator element. Another putative insulator occurs just downstream of FOXF1. Our results further strengthen the association between FOXF1 and a spectrum of malformations that include ACDMPV, atrioventricular septal defects, and gastrointestinal atresia. Furthermore, the presented analysis aids in defining the critical genomic region for this syndrome.

Neonatal deaths account for about 67% of all deaths during the first year of life in the USA. Genetic defects are important factors contributing to neonatal deaths and congenital anomalies. Here we report on the identification of a 1.37 Mb de novo deletion of chromosome 16q24.1-q24.2 by microarray-based comparative genomic hybridization (aCGH) technique in a newborn boy with lethal severe alveolar capillary dysplasia and multiple congenital anomalies who died of irreversible pulmonary hypertension, respiratory failure and cor pulmonale at three days of age. The phenotypic findings and causal genes (FOXF1 and FOXC2) involved in producing this unusual syndrome are detailed. Our findings independently confirm the results in a previous publication describing multiple patients with similar clinical and genetic observations, and highlight the importance of scanning human genomes at high resolution for identifications of micro-imbalances as pathogenic causes in neonates with unexplained congenital anomalies. (c) 2010 Wiley-Liss, Inc.