Genomic and genic deletions of the FOX gene cluster on 16q24.1 and inactivating mutations of FOXF1 cause alveolar capillary dysplasia and other malformations.

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare, neonatally lethal developmental disorder of the lung with defining histologic abnormalities typically associated with multiple congenital anomalies (MCA). Using array CGH analysis, we have identified six overlapping microdeletions encompassing the FOX transcription factor gene cluster in chromosome 16q24.1q24.2 in patients with ACD/MPV and MCA. Subsequently, we have identified four different heterozygous mutations (frameshift, nonsense, and no-stop) in the candidate FOXF1 gene in unrelated patients with sporadic ACD/MPV and MCA. Custom-designed, high-resolution microarray analysis of additional ACD/MPV samples revealed one microdeletion harboring FOXF1 and two distinct microdeletions upstream of FOXF1, implicating a position effect. DNA sequence analysis revealed that in six of nine deletions, both breakpoints occurred in the portions of Alu elements showing eight to 43 base pairs of perfect microhomology, suggesting replication error Microhomology-Mediated Break-Induced Replication (MMBIR)/Fork Stalling and Template Switching (FoSTeS) as a mechanism of their formation. In contrast to the association of point mutations in FOXF1 with bowel malrotation, microdeletions of FOXF1 were associated with hypoplastic left heart syndrome and gastrointestinal atresias, probably due to haploinsufficiency for the neighboring FOXC2 and FOXL1 genes. These differences reveal the phenotypic consequences of gene alterations in cis.

Practical toolkit for monitoring endoscope reprocessing effectiveness: Identification of viable bacteria on gastroscopes, colonoscopes, and bronchoscopes.

BACKGROUND: Experts have recommended microbiologic surveillance by external reference laboratories for certain flexible endoscopes. There is currently insufficient evidence on the feasibility and utility of cultures. Researchers evaluated a preassembled toolkit for collecting and processing samples from endoscopes. METHODS: A pilot study was performed in a large academic medical center. A toolkit was used to aseptically sample biopsy ports and suction/biopsy channels of 5 gastroscopes, 5 colonoscopes, and 5 bronchoscopes after full reprocessing. Blinded specimens were packaged and transported on icepacks to a reference laboratory that used standard methodologies for microbial cultures. RESULTS: The laboratory detected bacteria in samples from 60% of patient-ready endoscopes, including gram-positive and gram-negative species. Viable microbes (<10 CFU) were recovered from 2 gastroscopes, 3 colonoscopes, and 4 bronchoscopes. Stenotrophomonas maltophilia and Delftia acidovorans were recovered from all 3 endoscope types. Subsequent environmental testing detected S maltophilia in the reprocessing rinse water. CONCLUSIONS: A preassembled toolkit facilitated the aseptic collection of samples for culturing by a reference laboratory that detected viable microbes on fully reprocessed endoscopes. Speciation allowed identification of potential pathogens and a possible common contamination source, demonstrating that microbial cultures may have value even when colony counts are low.

Cytogenetically unrelated clones in different histologic components of a Wilms tumor.

Wilms tumor (WT) is a triphasic malignant neoplasm comprised of variable proportions of epithelial, blastemal, and mesenchymal (stromal) elements. Cytogenetic analysis of these tumors has revealed a number of recurring abnormalities, including hyperdiploidy and structural abnormalities of chromosomes 1, 7, 11, and 16. We describe a WT in which apparently unrelated cytogenetic clones were detected at diagnosis, when the predominant histologic component was blastema, and after therapy, when the tumor was composed primarily of stroma. At diagnosis, a pseudodiploid karyotype was present, characterized by an X;14 insertion with concurrent deletion of 14q. In contrast, the post-therapy specimen had a hyperdiploid karyotype with a constellation of gains typical for WT. The presence of clonal abnormalities in both the blastemal and mesenchymal components of a WT supports the hypothesis that the stromal component is neoplastic, rather than reactive. The clonal abnormalities seen in different histologic components of the same WT are typically related or identical. The finding in this case of apparently unrelated clones is unusual. Possible etiologies for this biclonality, and clinical implications, are discussed.