A novel mutation in TRMT5 associated with idiopathic non-cirrhotic portal hypertension and hepatopulmonary syndrome: Case report of two siblings.

Non-cirrhotic portal hypertension (NCPH) is a rare clinical entity in children. Familial clusters of idiopathic non-cirrhotic portal hypertension (INCPH) were previously reported in cases with deoxyguanosine kinase (DGOUK) and potassium calcium-activated channel subfamily N member 3 (KCNN3) mutations. Herein, we report two siblings who had a novel mutation in mitochondrial tRNA methyltransferase 5 (TRMT5) gene and presented with hepatopulmonary syndrome and later diagnosed as INCPH. Autosomal recessive inheritance of this mutation may suggest a role of TRMT5 mutations in the development of NCPH. Screening of TRMT5 mutations could be considered when familial INCPH is suspected.

Prevalence of histological features of idiopathic noncirrhotic portal hypertension in general population: a retrospective study of incidental liver biopsies.

BACKGROUND: Idiopathic noncirrhotic portal hypertension (INCPH) is associated with histologic changes secondary to obliterative portal venopathy without cirrhosis. We studied the prevalence of individual histological features of INCPH in liver biopsies obtained incidentally during unrelated elective procedures and in elective liver biopsies with the diagnosis of fatty liver disease. METHODS: A total of 53 incidental liver biopsies obtained intraoperatively during unrelated elective procedures and an additional 28 elective biopsies with the diagnosis of fatty liver disease without portal hypertension and cirrhosis were studied. Various histologic features of INCPH were evaluated. RESULTS: Shunt vessel (30%), phlebosclerosis (27%), increased number of portal vessels (19%) and incomplete septa (17%) were common in these liver biopsies after confounding factors such as co-existing fatty liver disease or fibrosis were excluded. At least one feature of INCPH was noted in 90% of the biopsies. Eight (10%) biopsies showed 5-6 features of INCPH. In total, 11 (14%) of 81 patients had risk factors associated with INCPH, including hypercoagulability, autoimmune disease, exposure to drugs, and infections. No patient had portal hypertension at the end of the follow-up. CONCLUSION: The histologic features of INCPH are seen in incidental liver biopsies and fatty liver disease without portal hypertension. Ten percent of the biopsies show 5-6 features of INCPH without portal hypertension. Interpreting histologic features in the right clinical context is important for proper patient care.