Choledochal Cyst with 17q12 Chromosomal Duplication

Area of Science:

• Genetics
• Pediatric Hepatology
• Medical Genetics

Background:

• The 17q12 chromosomal region contains the HNF1B gene, associated with various genetic disorders.
• Hepatobiliary abnormalities, including biliary atresia and choledochal cysts, can arise from genetic factors.

Purpose of the Study:

• To investigate 17q12 rearrangements in children with biliary atresia and/or choledochal cysts.
• To characterize the phenotype associated with HNF1B gene overdosage in a pediatric patient.

Main Methods:

• Screening for HNF1B/17q12 rearrangements in pediatric patients with specific biliary conditions.
• Detailed clinical, histological, and imaging assessment of an identified proband with a 17q12 duplication.

Main Results:

• A male proband with a 1698 kb 17q12 duplication including HNF1B was identified.
• The patient presented with infantile cholestatic jaundice due to a type Ia choledochal cyst, successfully treated with hepaticojejunostomy.
• Histology showed hepatic fibrosis and bile ductular proliferation; long-term follow-up revealed mild hepatomegaly without renal or hepatic cysts.

Conclusions:

• This is the first reported case of a hepatobiliary phenotype in a patient with HNF1B overdosage due to a 17q12 duplication.
• HNF1B overdosage can manifest with significant hepatobiliary complications in early life.