Clinical and histopathologic features of sodium taurocholate cotransporting polypeptide deficiency in pediatric patients

Abstract

Until now, the recognition of sodium taurocholate cotransporting polypeptide (NTCP) deficiency has been mainly based on sporadic case reports. It was previously believed to be mildly symptomatic and resulting in mild liver dysfunction. However, to our knowledge, there have been no reports about the histopathologic and ultrastructural pathologic characteristics of the disease. The aim of the study was to analyze the clinical, histopathologic and ultrastructural pathologic characteristics of NTCP deficiency in 13 pediatric patients.From August 2012 to October 2018, this retrospective study conducted in the Department of Pediatrics of Tongji Hospital, China analyzed the data of 13 NTCP deficient patients with an SLC10A1 gene mutation. Except for NTCP deficiency, no other liver diseases were present in the patients, which was determined by both a genetic testing panel for jaundice and by reviewing medical records. The laboratory results, imaging, histopathologic, and ultrastructural pathologic information were recorded for analysis.The serum level of total bile acid was high in all 13 patients. All patients had adequate growth and development. Eight of the patients (8/13) presented with visible jaundice and 12 (12/13) were found to have hyperbilirubinemia. A needle liver biopsy was performed in 11 cases, which revealed slightly chronic inflammation in all 11 patients. One of the patients (1/13) was found to be suffering from gallstones.The data showed that although NTCP deficiency was often asymptomatic, some of the patients showed obvious clinical expressions, such as jaundice. Among the 13 pediatric patients with NTCP deficiency, both the biochemical and histopathologic features were similar to those of mild hepatocellular jaundice. In addition, it was determined that the clinical features in the patient with gallstones may have been caused by NTCP deficiency.

Figure 1

Light microphotographs of H&E staining. (A) Normal structure of the liver lobule could be seen clearly. Mild fibrous proliferation and small bile duct proliferation were found at portal areas. (^∗100) (B) The cellular swelling and fatty degeneration were found in the hepatocytes. (^∗400) (C) Intrahepatocytic cholestasis could be seen. (^∗400) (D) Chronic inflammatory cells such as lymphocytes, aggregated at portal areas. (^∗400) (as depicted by the arrows).

Figure 2

Electronic microscope photographs. (A) Mildly increased lipid droplets were found in the cytoplasm. (^∗2000) (B) Cholestatic pigment granules deposited in the cytoplasm. (^∗5000) (C) Intercellular spaces were slightly dilated. Rough endoplasmic reticulum decreased and dilated. Smooth endoplasmic reticulum of hepatic cells proliferated. Hazy mitochondrial structures were seen under electron microscope. (^∗5000) (D) Slightly dilated bile capillaries and cholestasis in bile capillaries could be seen. (^∗5000) (E) Hepatic stellate cells and deposit of collagen fibers arranged in fascicular clusters in the Disse cavity were found. (^∗2000) (F) Fibers proliferated at portal areas. (^∗10000) (as depicted by the arrows).