studies

1034A AASLD ABSTRACTS HEPATOLOGY, October, 2015
Th1 cytokines (TNF-α and IFN-γ) and innate cytokines (IL-1, IL-6)
in WT-RRV mice but not BSS controls or Ig-α -/- RRV groups. Conclusions:
The RRV-induced mouse model of BA is associated
with an abnormal decrease in the expression of the majority
of transporters involved in bile excretion. The high levels of
retained bile acids may contribute to liver injury. The lack of
inflammation within the Ig-α -/- RRV mice is associated with normal
expression of the majority of bile acid transporter proteins,
suggesting that the inflammation present in RRV-induced BA
mice inappropriately inhibits bile acid transporter expression.
Disclosures:
The following authors have nothing to disclose: Asokan Rengasamy, Karim C.
El Kasmi, Brianna Traxinger, Jonathan Roach, Natarajan Balasubramaniyan,
Cara L. Mack
1693
Exome Sequencing and de novo Mutation Analysis
Reveal a Highly Connected Gene Network in Isolated
Biliary Atresia
Kathleen M. Loomes 5,1 , Ramakrishnan Rajagopalan 2 , Christopher
Grochowski 2 , Ying Chen 3,4 , Melissa Gilbert 2 , Henry C. Lin 5,1 , Marcella
Devoto 4,1 , Nancy B. Spinner 2,6 ; 1 Department of Pediatrics,
University of Pennsylvania Perelman School of Medicine, Philadelphia,
PA; 2 Department of Pathology and Laboratory Medicine, The
Children’s Hospital of Philadelphia, Philadelphia, PA; 3 Genomics
and Computational Biology Graduate Group, University of Pennsylvania
Perelman School of Medicine, Philadelphia, PA; 4 Division
of Human Genetics, The Children’s Hospital of Philadelphia,
Philadelphia, PA; 5 Division of Gastroenterology, Hepatology and
Nutrition, The Children’s Hospital of Philadelphia, Philadelphia,
PA; 6 Department of Pathology and Laboratory Medicine, University
of Pennsylvania Perelman School of Medicine, Philadelphia, PA
Biliary atresia (BA) is a severe pediatric liver disease resulting
in necroinflammatory obliteration of the extrahepatic biliary
tree. The majority of BA patients develop biliary cirrhosis and
50% will require liver transplantation in the first two years of
life. Incidence of BA is reported to be between 1 in 18,000
and 1 in 8,000 depending on ethnicity. The etiology of BA
is unknown, with evidence for infectious, environmental, and
genetic risk factors described. The purpose of this study was to
investigate possible genetic etiologies of BA by whole exome
sequencing of non-syndromic BA probands and their parents
(trios). DNA samples were obtained from 10 well-characterized
non-syndromic BA probands and their parents from the
NIDDK-funded Childhood Liver Disease Research Network
(ChiLDReN). We performed whole-exome sequencing in these
10 trios and looked for de novo mutations under the assumption
that mutations only seen in probands, but not the parents,
are more likely to be involved in the etiology of the disease.
We used a custom in-house computational analysis pipeline to
call variants and identify de novo mutations. We found a total
of 33 exonic de novo variants in 33 different genes. These
were 2 loss-of-function mutations, 3 in-frame insertions/deletions,
2 splice-site mutations and 26 missense mutations. The
number of de novo changes per proband ranged from 1 to 9
with a mean of 3.3. Seven of the 10 probands carried more
than 1 de novo mutation. However, none of the mutations was
seen in more than one proband. We used protein-interaction
network analysis tools such as GeneMANIA, DAPPLE and Ingenuity
Pathway Analysis (IPA) to assess 1) whether the genes
with de novo mutations are connected with each other directly
or through a single common partner, 2) whether the genes
with de novo mutations form a network with genes previously
implicated in BA. Gene network analysis with GeneMANIA
suggested a highly interconnected network of proteins that
are co-expressed. Protein interaction analysis with DAPPLE
suggested that 17 out of 33 genes (51%) interact with each
other directly or through a single common partner to form a
tight network. We used IPA to explore the paths between the
genes with de novo mutations and genes previously implicated
in BA. Network connectivity analyses with IPA suggest that
29 out of 33 genes (88%) are at most 2 nodes away from a
group of 19 selected BA candidate genes. Results from network
analysis suggest a shared etiology to seemingly sporadic de
novo mutations observed in probands with isolated BA. To our
knowledge, this is the first report of trio analysis for isolated BA
using next-generation sequencing technology.
Disclosures:
The following authors have nothing to disclose: Kathleen M. Loomes, Ramakrishnan
Rajagopalan, Christopher Grochowski, Ying Chen, Melissa Gilbert, Henry
C. Lin, Marcella Devoto, Nancy B. Spinner
1694
DXA Bone Density in Alagille Syndrome Correlates with
Fracture History and Degree of Cholestasis
Kathleen M. Loomes 2 , Cathie Spino 14 , Nathan P. Goodrich 1 ,
Thomas N. Hangartner 15 , Amanda E. Marker 15 , James E. Heubi 16 ,
Binita M. Kamath 13 , Benjamin Shneider 17 , Philip Rosenthal 3 ,
Paula M. Hertel 17 , Saul J. Karpen 4 , Nanda Kerkar 5,19 , Jean P.
Molleston 6 , Karen F. Murray 7 , Kathleen B. Schwarz 8 , Jeffrey Teckman
18 , Yumirle P. Turmelle 9 , Peter F. Whitington 20 , Averell H.
Sherker 10 , John C. Magee 11 , Ronald J. Sokol 12 ; 1 Arbor Research
Collaborative for Health, Ann Arbor, MI; 2 Pediatric Gastroenterology,
Hepatology and Nutrition, Children’s Hospital of Philadelphia,
Philadelphia, PA; 3 Division of GI, Hepatology and Nutrition,
UCSF-University of California, San Francisco, San Francisco, CA;
4 Pediatric Gastroenterology, Hepatology and Nutrition, Emory
University School of Medicine/Children’s Healthcare of Atlanta,
Atlanta, GA; 5 Children’s Hospital of Los Angeles, Los Angeles, CA;
6 Pediatric Gastroenterology, Hepatology and Nutrition, Indiana
University School of Medicine/Riley Hospital for Children, Indianapolis,
IN; 7 Division of Gastroenterology and Hepatology, University
of Washington Medical Center, Seattle Children’s, Seattle,
WA; 8 Johns Hopkins School of Medicine, Baltimore, MD; 9 Washington
University School of Medicine, Saint Louis, MO; 10 Liver Disease
Research Branch, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes of Health, Bethesda, MD;
11 University of Michigan Medical School, Ann Arbor, MI; 12 Section
of Pediatric Gastroenterology, Hepatology and Nutrition,
Department of Pediatrics, University of Colorado, Aurora, CO;
13 Division of Gastroenterology, Hepatology and Nutrition, Hospital
for Sick Children and University of Toronto, Toronto, ON, Canada;
14 University of Michigan, Ann Arbor, MI; 15 Department of
Biomedical, Industrial, & Human Factors Engineering, Wright State
University, Dayton, OH; 16 Division of Pediatric Gastroenterology,
Hepatology and Nutrition, Cincinnati Children’s Hospital Medical
Center, Cincinnati, OH; 17 Pediatric Gastroenterology, Hepatology
and Nutrition, Baylor College of Medicine, Houston, TX; 18 Saint
Louis University, Cardinal Glennon Children’s Medical Center,
St. Louis, MO; 19 Mount Sinai, New York, NY; 20 Department of
Pediatrics, Ann & Robert H. Lurie Children’s Hospital of Chicago,
Northwestern University Feinberg Medical School, Chicago, IL
Osteopenia and bone fractures (fx) are significant causes of
morbidity in children with cholestatic liver disease. We performed
dual energy X-ray absorptiometry (DXA) analysis in
a cohort of children with inherited cholestatic diseases and
explored associations with anthropometrics, laboratory measurements
and fx history. Methods: Subjects were enrolled
in the Longitudinal Study of Genetic Causes of Intrahepatic
Cholestasis (LOGIC) in the NIDDK-funded Childhood Liver