Genetic study of congenital bile-duct dilatation identifies de novo and inherited variants in functionally related genes.

BACKGROUND: Congenital dilatation of the bile-duct (CDD) is a rare, mostly sporadic, disorder that results in bile retention with severe associated complications. CDD affects mainly Asians. To our knowledge, no genetic study has ever been conducted. METHODS: We aim to identify genetic risk factors by a "trio-based" exome-sequencing approach, whereby 31 CDD probands and their unaffected parents were exome-sequenced. Seven-hundred controls from the local population were used to detect gene-sets significantly enriched with rare variants in CDD patients. RESULTS: Twenty-one predicted damaging de novo variants (DNVs; 4 protein truncating and 17 missense) were identified in several evolutionarily constrained genes (p < 0.01). Six genes carrying DNVs were associated with human developmental disorders involving epithelial, connective or bone morphologies (PXDN, RTEL1, ANKRD11, MAP2K1, CYLD, ACAN) and four linked with cholangio- and hepatocellular carcinomas (PIK3CA, TLN1 CYLD, MAP2K1). Importantly, CDD patients have an excess of DNVs in cancer-related genes (p < 0.025). Thirteen genes were recurrently mutated at different sites, forming compound heterozygotes or functionally related complexes within patients. CONCLUSIONS: Our data supports a strong genetic basis for CDD and show that CDD is not only genetically heterogeneous but also non-monogenic, requiring mutations in more than one genes for the disease to develop. The data is consistent with the rarity and sporadic presentation of CDD.

Laparoscopic management of abdominal lymphatic cyst in children.

PURPOSE: The aim of this study is to investigate the feasibility and effectiveness of laparoscopic surgery (LS) in management of abdominal lymphatic cyst (ALC) in children. SUBJECTS AND METHODS: Medical records of all patients undergoing LS for ALC at the National Hospital of Pediatrics, Hanoi, Vietnam, from May 2007 to June 2011 were reviewed. For LS, one umbilical port of 10 mm and up to three other 3-5-mm ports were used. Cystic fluid was aspirated prior to removal of the cyst. When intestinal resection was indicated, the mesenteric cyst with the bowel loop was delivered out of the abdomen through a minimally enlarged umbilical incision; resection of the intestinal segment together with the cyst and the bowel anastomosis were both performed extracorporally. RESULTS: Forty-seven patients were identified, with a mean age of 4.3 ± 3.7 years. The most common symptoms were abdominal pain (72.3%) and abdominal distention (34.0%). Four patients presented with acute abdomen due to infection or hemorrhage of the cyst. Mean size of the ALC was 9.5 ± 5.5 cm (range, 3.4-30 cm). In 12 cases the ALC was omental, and in 35 cases it was mesenteric. Laparoscopic cyst excision was performed in 36 cases (76.6%) versus laparoscopy-assisted bowel resection en bloc with the cyst in 8 cases (17.0%); in 3 patients (6.4%), conversion to open surgery was required. Mean operative time was 79 ± 39 minutes. There were no intra- or postoperative complications. Mean length of hospital stay after laparoscopic management was 3.8 ± 1.6 days. The results of pathologic investigation showed benign cystic lymphangioma in all cases. During follow-up ranging from 1 month to 4 years, recurrence was seen in 1 patient (2.1%) with complex mesenteric cyst. All other patients remained in good health. CONCLUSIONS: Laparoscopic management is safe, feasible, and effective and should be the treatment of choice for most cases of ALC in children.