Genetic Defects in Bile Acid Conjugation Cause Fat-soluble Vitamin Deficiency

Kenneth D. R. Setchell; James E. Heubi; Sohela Shah; Joel E. Lavine; David Suskind; Mohammed Al–Edreesi; Carol Potter; David W. Russell; Nancy C. O'Connell; Brian Wolfe; Pinky Jha; Wujuan Zhang; Kevin E. Bove; Alex S. Knisely; Alan F. Hofmann; Philip Rosenthal; Laura N. Bull

Disclosures

Gastroenterology. 2013;144(5):945-955. 

In This Article

Supplementary Patients and Methods

Ten patients from 7 different families are presented, and the demographics and main clinical presentations are summarized in Table 1. A more detailed description of these patients follows.

Patient 1 was a male infant born weighing 2.6 kg after an uncomplicated term pregnancy in an 18-year-old primigravida of Laotian descent. Specific details on his parents are not available. He presented at age 40 days with jaundice and anemia (serum total bilirubin level of 10 mg/dL, direct bilirubin level of 5 mg/dL, hemoglobin level of 8.5 g/dL, and reticulocyte count of 11%). Hemoglobin electrophoresis found Hemoglobin H with Constant Spring, a form of α-thalassemia with an α-hemoglobin chain variant.[1] At age 90 days, laboratory values were as follows: total bilirubin, 21 mg/dL; alanine aminotransferase (ALT), 216 IU/L; aspartate aminotransferase (AST), 294 IU/L; lactate dehydrogenase, 765 IU/L; and alkaline phosphatase, 466 IU/L. Findings on hepatobiliary iminodiacetic acid scanning and on ultrasound evaluations of the liver and gallbladder were normal. At age 5 months, he presented with failure to thrive, voluminous stools, epistaxis, and hematochezia. Physical examination revealed weight and height below the 5th percentile and marked hepatosplenomegaly but no ascites. His skin bore petechiae and ecchymoses. PT was 83 seconds (control, 10 seconds) and partial thromboplastin time (PTT) was 200 seconds (control, 30 seconds); these values normalized after administration of fresh-frozen plasma and vitamin K. Light microscopy of a percutaneous liver biopsy specimen found marked bile duct proliferation with bile plugs, hepatocellular pseudo-acini with intrahepatocytic cholestasis, sinusoidal disarray, expanded portal tracts with infiltration of neutrophils and lymphocytes, and mild bridging fibrosis, without extramedullary hematopoiesis. He remained on oral vitamin K (2.5 mg/day) for 4 years. Voluminous stools were treated with a change in formula to one with significant amounts of medium-chain triglycerides and hydrolyzed cow milk protein. At 1 year of age, the patient was admitted with anemia, congestive heart failure, and pulmonary edema. He had radiographic evidence of rickets with a fracture of the proximal fibula. Laboratory evaluation revealed the following: serum calcium, 6.5 mg/dL; phosphorus, 2.1 mg/dL; magnesium, 2.2 mg/dL; alkaline phosphatase, 1090 IU/L; ALT, 32 IU/L; AST, 26 IU/L; direct bilirubin, 1.4 mg/dL; albumin, 3.2 g/dL; and total protein, 6.5 g/dL. He responded to treatment with ergocalciferol and calcium supplements and remained on ergocalciferol for 4 years. The patient required multiple blood transfusions due to his hemoglobinopathy and treatment with the iron chelator deferoxamine throughout his childhood. No further evaluation of his liver or digestive problems was performed until age 14 years, when physical examination revealed marked growth retardation and hepatosplenomegaly. Laboratory evaluations revealed markedly decreased serum concentrations of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, carotene, and vitamin K. Serum ALT and total and direct bilirubin levels were normal Table 1). Hepatobiliary ultrasound studies showed hepatomegaly with homogeneity and no gallstones. At liver biopsy, severe hemosiderosis within hepatocytes and Kupffer cells, a well-preserved liver lobular architecture, minimal periportal fibrosis, and mild focal portal inflammation were seen; cholestasis and ductular proliferation had resolved. A urine sample was then screened for a bile acid synthetic defect using mass spectrometry.

Patient 2 was a male infant, the third baby born to Saudi Arabian parents who were first cousins. He had a normal delivery at term and weighed 3.3 kg. A 7-year-old brother and an 8-year-old sister were reportedly both healthy. There was no history of liver disease in either parent's family. He was admitted at age 28 days because of worsening jaundice since birth, weighing 3.8 kg (75th percentile) with acholic stools. Physical findings included a slightly enlarged liver without splenomegaly. Laboratory tests revealed the following: total bilirubin, 18 mg/dL; direct bilirubin, 13 mg/dL; AST, 185 IU/L; ALT, 228 IU/L; and alkaline phosphatase, 863 IU/L. Ultrasonography failed to identify the gallbladder or common bile duct, although the liver was reportedly of normal size with slightly nonhomogeneous echogenicity. Hepatobiliary iminodiacetic acid scanning showed no excretion of isotope into the intestine. At age 40 days, an intraoperative cholangiogram revealed opacified intrahepatic ducts and small hypoplastic cystic and common bile ducts with contrast seen in the duodenum. Extrahepatic biliary hypoplasia was diagnosed, and a portoenterostomy was performed at the surgeon's discretion. At age 3 months, the patient was asymptomatic and gaining weight. Serum total bilirubin level was 7.4 mg/dL, and direct bilirubin level was 6.7 mg/dL. The liver was firm. At age 7 months, a fracture of the right humerus and rickets were identified. The patient was noncompliant to oral fat-soluble vitamins. A low serum vitamin E level (1.7 mg/dL) was measured at age 9 months. Regular administration of Aquasol E (Columbus Labs, Ottawa, Ontario, Canada) did not result in any significant change in the vitamin E level after 1 month. A vitamin A level was normal, as were PT and PTT values. Pruritus developed at age 1 year, and he was started on ursodeoxycholic acid 4 months later (10 mg/kg body wt per day). Growth and development continued normally, and pruritus persisted. Serum vitamin E levels were persistently low. At age 4 years, urine and serum samples were screened for a bile acid synthetic defect. A follow-up liver biopsy was also performed at that time. He was then lost to follow-up until age 15.5 years, when he presented with severe bilateral knee valgus deformity and low serum vitamin D and E levels. His weight was 32.7 kg (<3rd percentile) and body mass index was 15.7 kg/m2; he reported no pruritus. On examination, he was nonicteric with a 2-cm firm liver, no splenomegaly, and no evidence of portal hypertension. Liver disease was substantial, as evidenced by elevated serum transaminase (2× the upper limit of normal), alkaline phosphatase (20× the upper limit of normal), and serum total bile acid levels (99 μmol/L). His serum GGT and bilirubin levels were normal. Ultrasonography showed mild coarsening of liver echotexture but no evidence of portal hypertension.

Patient 3 was the 8-year-old sister of patient 2. Clinical information about this patient was not available at the time of diagnosis because the father claimed the child was asymptomatic and refused medical examination other than screening of urine and serum samples by mass spectrometry for a bile acid synthetic defect. The early clinical history is scant; a chest x-ray showed cupping of anterior ribs consistent with rickets at age 6 months, and she had fractures of the right 3rd and 4th fingers with high serum alkaline phosphatase and phosphorus levels at age 3 years. At age 12 years, serum vitamin E level was low (3.8 mg/mL), with a normal vitamin A level and normal serum transaminase level, GGT level, PT, and PTT. At age 15 years, her weight was 53 kg (50th percentile).

Patient 4 was a 2.3-kg female infant born to a secundigravida by cesarean section at 36 weeks' gestation because of preeclampsia. There was no parental consanguinity or family history of liver disease, growth failure, or diarrhea. A 4-year-old brother was well. On routine 4-month immunizations, the patient developed large ecchymoses on both legs immediately after injections and a complete blood cell count revealed a hemoglobin level of 4.6 g/dL with 182,000/mm3 platelets and a leukocyte count of 3900/mm3. PT was >110 seconds, and PTT was 100 seconds. Plasma fibrinogen concentrations were normal. The patient received packed red blood cells, vitamin K, and fresh-frozen plasma, and her coagulopathy resolved. She weighed 5.2 kg, and her height was 57.5 cm (both <3rd percentile for age). There was no hepatosplenomegaly, ascites, or edema. Serum AST, ALT, and bilirubin levels were normal. Ultrasonography of the abdomen revealed no abnormalities. Serum levels of vitamin A were normal (34 μg/L; expected, 20–43 μg/L) with low serum levels of 25-hydroxyvitamin D (9 ng/mL; expected, >20 ng/mL) and vitamin E (< 1.5 mg/dL; expected, 3–15 mg/dL). Skeletal radiography revealed moderate to severe rickets. The patient was begun on water-soluble vitamins A, D, E, and K (ADEK; Axcan Scandipharm, Inc, Birmingham, AL) and elemental formula. Over the next month, the patient's fat-soluble vitamin deficiency resolved (serum vitamin A, 47.7 μg/L; vitamin E, 7.7 mg/dL) but her weight for age and height worsened, falling further below the 3rd percentile, and serum transaminase values rose mildly (AST, 46 IU/L; ALT, 66 IU/L) with normal serum GGT and bilirubin levels. Percutaneous liver biopsy was performed at age 15 months to investigate mild transaminasemia. A nasogastric tube was placed, and the patient was given a minimum of 4 cans of Peptamen Junior (medium-chain triglyceride–containing formula; Nestle Nutrition, Vevey, Switzerland) per day with improvement in growth. Urine and serum samples from the child were screened for a bile acid synthetic defect.

Patient 5 was a 5½-month-old male infant with a history of developmental delay; he was the 5th of 6 siblings born to parents who shared a pair of great-great-grandparents. He was born at term weighing 4.58 kg following an uneventful pregnancy and was admitted to the hospital at age 2 days for hydrocephalus ascribed to aqueductal stenosis and for jaundice, respiratory distress, hypoglycemia, and possible sepsis. He was moderately icteric (total bilirubin, 13.8 mg/dL; direct bilirubin, 2.3 mg/dL) with petechiae over the right eyebrow. The abdomen was soft and without hepatosplenomegaly. Computed tomography of the brain showed dilated lateral ventricles and large third ventricles. Phototherapy was given, and a ventricular shunt was placed. He developed progressive liver failure with prolonged international normalized ratio (INR) and underwent evaluation, including liver biopsy, for liver transplantation. A urine sample was screened for inborn errors of bile acid synthesis. The patient subsequently received a liver allograft from a deceased donor; his course thereafter was benign.

Patient 6 was the sister of patients 5 and 7. She was in excellent health with a history of only a single urinary tract infection, for which she received intravenous antibiotics. At age 9 years, her height was 134.9 cm (50th percentile), weight 32.7 kg (50th percentile), and body mass index 18 kg/m2 (80th percentile), without abnormality on physical examination, including absence of jaundice and hepatosplenomegaly. PT was 12.6 seconds with an INR of 1.0. Serum alkaline phosphatase level was 384 IU/L, AST level was 30 IU/L, ALT level was 17 IU/L, and total bilirubin level was 0.4 mg/dL. Serum 25-OH vitamin D level was 25 ng/mL (expected, >20 ng/mL), vitamin A level was 24 μg/L (expected, 26–72 μg/L), and total tocopherol levels were low at 3 mg/dL (expected, 3–15 mg/dL). A urine sample was screened for a bile acid synthetic defect.

Patient 7 was the sister of patients 5 and 6. Severe jaundice as a neonate prompted extensive evaluation (including liver biopsy; findings unavailable). All results of genetic studies were normal. Her parents were told that she had hepatitis but were given no further information. She was subsequently treated with ursodeoxycholic acid until approximately 3 years of age and was given vitamin A until 5 years of age. No further treatments or diagnostic studies were performed. At age 4 years, severe anemia was treated with iron. When screened for an inborn error of bile acid amidation at age 10 years, her height was 134.6 cm (10th percentile), weight was 26.3 kg (10th percentile), and body mass index was 16.2 kg/m2 (25th percentile). Physical examination showed neither jaundice nor hepatosplenomegaly. Laboratory results included a PTT of 14.9 seconds with an INR of 1.2, AST level of 50 IU/L, ALT level of 33 IU/L, and total bilirubin level of 0.5 mg/dL. Serum 25-hydroxyvitamin D level was low at 12 ng/mL, and serum vitamin A level was marginally low at 21 μg/L with total tocopherol levels reduced at 0.3 mg/dL.

Patient 8 was a female infant, born at term weighing 3.63 kg to an Amish secundigravida, who presented at age 4 months with growth failure and unexplained fat-soluble vitamin deficiency. There was no family history of liver disease, malabsorption, or growth failure. Her sibling was well. Physical examination was unremarkable; she weighed 5.64 kg (25th percentile) with a height of 63.2 cm (25th percentile). Laboratory values were as follows: total serum bilirubin, 0.4 mg/L with 0 mg/dL direct; ALT, 19 IU/L; AST, 54 IU/L; alkaline phosphatase, 2108 IU/L; and GGT, 10 IU/L. Serum α-tocopherol level was 1.8 mg/dL (expected, 3–15 mg/dL), retinol level was 0.36 μmol/L (expected, 0.63–1.75 μmol/L), serum 25-hydroxyvitamin D level was <5 ng/mL, and PTT was >120 seconds, which normalized with parenteral vitamin K. A urine sample was screened for a bile acid synthetic defect using mass spectrometry.

Patient 9 was a male infant weighing 2.5 kg at birth after a 34-week pregnancy, complicated by glucose intolerance, in a 37-year-old Hispanic woman. It was her 6th pregnancy; no information is available on the patient's 5 siblings. There was no family history of liver disease, growth failure, or rickets. He was evaluated at age 5 months for jaundice, growth retardation, rickets, and hypocalcemia. Physical examination revealed jaundice and mild hepatomegaly with no splenomegaly or ascites. PT was 24.5 seconds with an INR of 2.2. Laboratory studies showed the following: total bilirubin, 10.1 mg/dL (direct, 7.8 mg/dL); albumin, 4.3 g/dL; alkaline phosphatase, 1716 IU/L; total calcium, 5.9 mg/dL; AST, 756 IU/L; ALT, 37 IU/L; hemoglobin, 12 g/dL; and platelet count, 450,000/mm3. PT values normalized with parenteral vitamin K. Serum 25-hydroxyvitamin D level was 14.5 ng/mL (expected, >20 ng/mL), and vitamin E level was <1.5 mg/dL (expected, 3–15 mg/L). Light microscopy of a liver biopsy specimen showed giant cell transformation of hepatocytes. He was given intravenous calcium, fat-soluble vitamins, ursodeoxycholic acid, and Alimentum (a medium-chain triglyceride–based formula; Abbot Nutrition, Columbus, OH). A urine sample was screened for a bile acid synthetic defect using mass spectrometry.

Patient 10 was a 10-year-old girl evaluated for poor weight gain. Weight was 20.9 kg (<5th percentile); findings on physical examination were otherwise unremarkable. She received intensive nutritional therapy by nasogastric tube but had only modest weight gain. A urine sample was screened for a bile acid synthetic defect in 2006, when the child 8 years of age, and again at 10 years of age. She subsequently was hospitalized for operative repair of duodenal stenosis and has been lost to follow-up.

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