[Clinical and genetic analysis of eleven pediatric patients with Alagille syndrome].

Objective: To explore the clinical and molecular genetic features of patients with Alagille syndrome (AS). Methods: The clinical data of eleven pediatric patients, who were suspected to have AS at the Department of Pediatrics in the First Affiliated Hospital of Jinan University from August 2010 to March 2017, were collected and analyzed. Genomic DNA was extracted from peripheral blood leukocytes of the patients and their parents. For 5 patients collected before March 2006, all JAG1 exons and their flanking sequences were directly sequenced. For the remaining 6 patients, high-throughput gene capture technology, chromosomal microarray analysis (CMA) and whole-genome copy-number variant(CNV) analysis were utilized, when necessary, to explore the genetic causes. Results: All patients had cholestasis. However, the γ-glutamyl transpeptidase (GGT) levels in one patient were normal. Nine patients had posterior embryotoxon and facial malformations. Eight patients displayed heart defects. Seven patients presented with vertebral anomalies and among them, 1 patient had sacralization of the cubitus and radius. The condition of nine patients tended to be stabilized on follow-up, but 1 patient died of liver failure in late infancy and 1 got worse. Seven JAG1 variants were detected in 9 out of the 11 AS patients, with c.1977G>A (p.Trp659*) and c.1106_1107delCC (p.Pro369fs) being two novel variants. Two heterozygous interstitial deletions of 3.0 Mb and 9.24 Mb in size, respectively, in chromosome 20 were discovered in the remaining 2 patients. Both deletions involved the entire JAG1 gene. De novo origin was unveiled for the detected variants in 7 patients and interstitial deletions in two. Although the mother of 2 patients carried the relevant variant, she did not demonstrate any clinical features of AS. Conclusions: With cholestasis, posterior embryotoxon, facial malformations, heart defects and vertebral anomalies being the major manifestations, AS demonstrated variable clinical expressivities and incomplete penetrance. This study identified a total of 7 JAG1 variants as well as 2 interstitial deletions involving this gene, and among them, the variants c.1977G>A (p.Trp659* ) and c.1106_1107delCC (p.Pro369fs) as well as the 9.24 Mb chromosomal interstitial deletion had not been reported previously.