Congenital portosystemic venous shunt associated with 22q11.2 deletion syndrome: a case report

22q11.2 deletion syndrome (22qDS) is the most common chromosomal microdeletion syndrome and is associated with a high rate of congenital heart disease (CHD) and neurodevelopmental abnormalities. Congenital portosystemic venous shunts (CPSS) are rare developmental abnormalities of the portal venous system. The clinical manifestations of CPSS are varied, and some patients have CHD or genetic chromosomal abnormalities, but their relationship remains unknown. We report the first case of CPSS associated with 22qDS.

A newborn boy referred to our institution was diagnosed with 22qDS due to characteristic facial features and complications of tetralogy of Fallot. A subsequent newborn screening test indicated hypergalactosemia and high blood levels of ammonia and bile acids. Upon closer examination, these abnormalities were found to be caused by the CPSS. Abdominal contrast-enhanced computed tomography and angiography confirmed that abnormal blood vessels ascended from the splenic vein and short-circuited to the left renal vein. Intracardiac repair for CHD was performed at 1 year of age, followed by transcatheter occlusion of the CPSS using a multilayer device (vascular plug) and detachable coil at 2 years of age. After treatment, the abnormal blood parameters promptly normalized.

As the blood flow of CPSS bypasses the liver, the levels of galactose, bile acids, and ammonia in the systemic veins can increase. Some patients with CPSS have CHD, and these toxic substances may cause liver and lung lesions as well as portosystemic encephalopathy (PSE). Several genetic chromosomal abnormalities, including 22qDS, and CPSS have similar symptoms, and neurodevelopmental abnormalities, particularly those caused by PSE, may be difficult to diagnose. Blood tests, such as newborn screening, and abdominal imaging are useful in the early diagnosis of CPSS.