Deciphering an isolated lung phenotype of NKX2-1 frameshift pathogenic variant

Backgroundto perform a functional analysis of a new NK2 homeobox 1 (NKX2-1) variant (c.85_86del denominated NKX2-1DEL) identified in a family presenting with isolated respiratory disease, in comparison to another frameshift variant (c.254dup denominated NKX2-1DUP) identified in a subject with classical brain-lung-thyroid syndrome.Methodspathogenic variants were introduced into the pcDNA3-1(+)-wt-TTF1 plasmid. The proteins obtained were analyzed by western blot assay. Subcellular localization was assessed by confocal microscopy in A549 and Nthy cells. Transactivation of SFTPA, SFTPB, SFTPC, and ABCA3 promoters was assessed in A549 cells. Thyroglobulin promoter activity was measured with the paired box gene 8 (PAX8) cofactor in Nthy cells.ResultsThe two sequence variants were predicted to produce aberrant proteins identical from the 86th amino acid, with deletion of their functional homeodomain, including the nuclear localization signal. However, 3D conformation prediction of the conformation prediction of the mutant protein assumed the presence of a nuclear localization signal, a bipartite sequence, confirmed by confocal microscopy showing both mutant proteins localized in the nucleus and cytoplasm. Transcriptional activity with SFTPA, SFTPB, SFTPC, ABCA3 and thyroglobulin promoters was significantly decreased with both variants. However, with NKX2-1DEL, thyroglobulin transcriptional activity was maintained with the addition of PAX8.ConclusionThese results provide novel insights into understanding the molecular mechanism of phenotypes associated with NKX2-1 pathogenic variants

Magnetic resonance imaging in the prenatal diagnosis of congenital diarrhea

Objective Congenital diarrhea is very rare, and postnatal diagnosis is often made once the condition has caused potentially lethal fluid loss and electrolyte disorders. Prenatal detection is important to improve the immediate neonatal prognosis. We aimed to describe the prenatal ultrasound and magnetic resonance (MRI) imaging findings in fetuses with congenital diarrhea. Methods The study reports the pre- and postnatal findings in four fetuses that presented with generalized bowel dilatation and polyhydramnios. We analyzed the fetal ultrasound and MRI examinations jointly, then compared our provisional diagnosis with the amniotic fluid biochemistry and subsequently with the neonatal stool characteristics. Results In each of the four cases an ultrasound examination between 22 and 30 weeks' gestation showed moderate generalized bowel dilatation and polyhydramnios suggesting intestinal obstruction. MRI examinations performed between 24 and 32 weeks' gestation confirmed that the dilatation was of gastrointestinal (GI) origin, with a signal indicating intraluminal water visible throughout the small bowel and colon. The expected hypersignal on T1-weighted sequences characteristic of physiological meconium was absent in the colon and rectum. This suggested that the meconium had been completely diluted and flushed out by the water content of the bowel. The constellation of MRI findings enabled a prenatal diagnosis of congenital diarrhea. The perinatal lab test findings revealed two cases of chloride diarrhea and two of sodium diarrhea. Conclusion Congenital diarrhea may be misdiagnosed as intestinal obstruction on prenatal ultrasound but has characteristic findings on prenatal MRI enabling accurate diagnosis; this is important for optimal neonatal management. Copyright © 2010 ISUOG.SCOPUS: ar.jFLWINinfo:eu-repo/semantics/publishe

Deciphering an isolated lung phenotype of NKX2-1 frameshift pathogenic variant

Background to perform a functional analysis of a new NK2 homeobox 1 (NKX2-1) variant (c.85_86del denominated NKX2-1 DEL ) identified in a family presenting with isolated respiratory disease, in comparison to another frameshift variant (c.254dup denominated NKX2-1 DUP ) identified in a subject with classical brain-lung-thyroid syndrome. Methods pathogenic variants were introduced into the pcDNA3-1(+)-wt-TTF1 plasmid. The proteins obtained were analyzed by western blot assay. Subcellular localization was assessed by confocal microscopy in A549 and Nthy cells. Transactivation of SFTPA , SFTPB , SFTPC , and ABCA3 promoters was assessed in A549 cells. Thyroglobulin promoter activity was measured with the paired box gene 8 (PAX8) cofactor in Nthy cells. Results The two sequence variants were predicted to produce aberrant proteins identical from the 86th amino acid, with deletion of their functional homeodomain, including the nuclear localization signal. However, 3D conformation prediction of the conformation prediction of the mutant protein assumed the presence of a nuclear localization signal, a bipartite sequence, confirmed by confocal microscopy showing both mutant proteins localized in the nucleus and cytoplasm. Transcriptional activity with SFTPA, SFTPB, SFTPC, ABCA3 and thyroglobulin promoters was significantly decreased with both variants. However, with NKX2-1 DEL , thyroglobulin transcriptional activity was maintained with the addition of PAX8. Conclusion These results provide novel insights into understanding the molecular mechanism of phenotypes associated with NKX2-1 pathogenic variants