Christiane Baussan

ATP8B1 and ABCB11 analysis in 62 children with normal gamma-glutamyl transferase progressive familial intrahepatic cholestasis (PFIC): phenotypic differences between PFIC1 and PFIC2 and natural history

Progressive familial intrahepatic cholestasis (PFIC) types 1 and 2 are characterized by normal serum gamma‐glutamyl transferase (GGT) activity and are due to mutations in ATP8B1 (encoding FIC1) and ABCB11 (encoding bile salt export pump [BSEP]), respectively. Our goal was to evaluate the features that may distinguish PFIC1 from PFIC2 and ease their diagnosis. We retrospectively reviewed charts of 62 children with normal‐GGT PFIC in whom a search for ATP8B1 and/or ABCB11 mutation, liver BSEP immunostaining, and/or bile analysis were performed. Based on genetic testing, 13 patients were PFIC1 and 39 PFIC2. The PFIC origin remained unknown in 10 cases. PFIC2 patients had a higher tendency to develop neonatal cholestasis. High serum alanine aminotransferase and alphafetoprotein levels, severe lobular lesions with giant hepatocytes, early liver failure, cholelithiasis, hepatocellular carcinoma, very low biliary bile acid concentration, and negative BSEP canalicular staining suggest PFIC2, whereas an absence of these signs and/or presence of extrahepatic manifestations suggest PFIC1. The PFIC1 and PFIC2 phenotypes were not clearly correlated with mutation types, but we found tendencies for a better prognosis and response to ursodeoxycholic acid (UDCA) or biliary diversion (BD) in a few children with missense mutations. Combination of UDCA, BD, and liver transplantation allowed 87% of normal‐GGT PFIC patients to be alive at a median age of 10.5 years (1‐36), half of them without liver transplantation. Conclusion: PFIC1 and PFIC2 differ clinically, biochemically, and histologically at presentation and/or during the disease course. A small proportion of normal‐GGT PFIC is likely not due to ATP8B1 or ABCB11 mutations. (HEPATOLOGY 2010)

CFC1 gene involvement in biliary atresia with polysplenia syndrome.

The present report describes CFC1 gene analysis in 10 patients with polysplenia syndrome. The heterozygous transition c.433G>A (Ala145Thr) located in exon 5 was identified in 5 patients, with a twice-higher frequency than in control patients. These results suggest that heterozygous CFC1 mutation may represent a genetic predisposition to biliary atresia splenic malformation syndrome.

Successful Treatment of Severe Cardiomyopathy in Glycogen Storage Disease Type III With D,L-3-Hydroxybutyrate, Ketogenic and High-Protein Diet

Glycogen storage disease type III (GSD III) due to debranching enzyme deficiency presenting usually with hepatomegaly and hypoglycemia may be responsible for severe cardiomyopathy which is often fatal. Current treatment of GSD III is based on frequent high-carbohydrate meals that have no effect on the cardiomyopathy. We describe a 2-mo-old infant presenting with a familial form of GSD III complicated with cardiomyopathy. As conventional treatment was unable to improve his sisters cardiomyopathy who was deceased at age 11 mo, we proposed an experimental treatment combining the use of synthetic ketone bodies (d,l-3-OH butyrate) as an alternative energy source, 2:1 ketogenic diet to reduce glucose intake and high-protein diet to enhance gluconeogenesis. Twenty-four months after the onset of this treatment, echocardiography showed an improvement of cardiomyopathy. Growth and liver size remained normal, and no side effects were observed. Blood glucose levels remained within the normal range and insulin levels decreased. These findings show that synthetic ketone bodies as well as low-carbohydrate, high-lipid, and high-protein diet may be a more beneficial therapeutic choice therapeutic choice for GSD III patients with cardiomyopathy. These encouraging data need to be confirmed in more GSD III patients presenting with cardiac or muscular symptoms.

Prenatal molecular diagnosis of inherited cholestatic diseases

Objectives: Progressive familial intrahepatic cholestasis (PFIC) and to a lesser extent, Alagille syndrome, often lead to end-stage liver disease during childhood. We report our experience of DNA-based prenatal diagnosis of PFIC1–3 and Alagille syndrome. Patients and Methods: Four molecular antenatal diagnoses were performed in 3 PFIC families and 17 in 11 Alagille syndrome families. DNA was isolated from chorionic villus or cultured amniocyte samples from women, without pregnancy complications. Results: All four foetuses with a family history of PFIC1, 2, or 3 were heterozygous for an ATP8B1, ABCB11, or ABCB4 mutation and pregnancies were continued. Three of the infants were healthy after birth, and 1 premature infant, who had an ABCB4 mutation, experienced transient neonatal cholestasis. Among the families with a history of de novo JAG1 mutation, none of the foetuses was mutated, versus 40% of those with a history of familial mutation. Of 4 pregnant women with a JAG1-mutated foetus, 3 cut short their pregnancy and 1 gave birth to a child with overt Alagille syndrome. Conclusions: Molecular antenatal diagnosis of PFIC1–3 and Alagille syndrome is reliable because clinical outcome after birth corresponded to molecular foetal data.

Evaluation of FibroTest-ActiTest in children with chronic hepatitis C virus infection.

FibroTest-ActiTest (FT-AT) has been validated in adults with chronic hepatitis C virus (HCV) infection as a noninvasive alternative to liver biopsy (LB), but there are few data of its use in children. The objective of the present study was to evaluate FT-AT in children with HCV infection and to compare FT-AT analysis with liver histology. A total of 43 serum samples from 38 children with chronic HCV infection were analyzed retrospectively. Histological evaluation was performed according to the METAVIR scoring system. In 16 of the children, 21 serum samples were tested with FT-AT and compared to 21 LB (serum/LB pairs) in nontransplanted and liver-transplanted children. FT-AT was also measured in 22 infected children without LB and in 50 healthy controls. FT-AT values in controls were comparable to those of healthy adults, validating the adult FT-AT parameters in children. In most infected children (74%), the FT-AT score was <or = A1-F1. Concordance between FT-AT and METAVIR scores was found in 10 pairs and discordance in 11. FT-AT/METAVIR concordance was better in non-transplanted (8/13 pairs, 62%) than in transplanted (2/8 pairs, 25%) children. A prospective evaluation of FT-AT in non-transplanted children with chronic HCV infection would be worthwhile in future.

Genetic hypoglycaemia in infancy and childhood: Pathophysiology and diagnosis

Glucose, like oxygen, is of essential and fundamental importance for brain metabo- lism. The major source of brain glucose is the blood supply and thus a severe encephalopathy will ensue when the glucose content of blood becomes de—cient. A prompt diagnosis is essential and must be achieved safely with an appropriate test. This requires knowledge of the homeostatic mechanisms that maintain the blood glucose concentration between the relatively narrow range of 2.5 and 7.5 mmol/L whether the child is eating or fasting. Within the last decade, many new insights and facts have expanded our knowledge considerably in elucidating the causes and mechanisms of genetic hypoglycaemias. This brief review outlines certain aspects of the regulation of glucose homeostasis and focuses on the causes of genetic hypogly- caemias, in which signi—cant advances have been made recently. DEFINITION After the —rst 72 h of life (term babies) or the —rst week (pre-term babies), hypogly- caemia is generally de—ned as a plasma or capillary whole-blood glucose concentra- tion less than 2.5 mmol/L (Walker 1994). Although it is highly controversial (Cornblath et al 1990; Volpe 1995), there is a growing consensus that in neonates levels above 2.5 mmol/L are desirable. Moreover, and most importantly, these lower limits are probably exceeded when concomitant insults that increase cerebral demand for glucose (like hypoxaemia and ischaemia) accompany hypoglycaemia.

Hereditary fructose intolerance: Frequency and spectrum mutations of the aldolase B gene in a large patients cohort from France—Identification of eight new mutations

We investigated the molecular basis of hereditary fructose intolerance (HFI) in 160 patients from 92 families by means of a PCR-based mutation screening strategy, consisting of restriction enzyme digestion and direct sequencing. Sixteen different mutations of the aldolase B (ALDOB) gene were identified in HFI patients. As in previous studies, p.A150P (64%), p.A175D (16%) and p.N335K (5%) were the most common mutated alleles, followed by p.R60X, p.A338V, c.360_363delCAAA (p.N120KfsX30), c.324G>A (p.K108K) and c.625-1G>A. Eight novel mutations were also identified in 10 families with HFI: a one-base deletion (c.146delT (p.V49GfsX27)), a small deletion (c.953del42bp), a small insertion (c.689ins TGCTAA (p.K230MfsX136)), one splice site mutation (c.112+1G>A), one nonsense mutation (c.444G>A (p.W148X)), and three missense mutations (c.170G>C (p.R57P), c.839C>A (p.A280P) and c.932T>C (p.L311P)). Our strategy allows to diagnose 75% of HFI patients using restriction enzymatic analysis and to enlarge the diagnosis to 97% of HFI patients when associated with direct sequencing.

Liver glycogen storage diseases due to phosphorylase system deficiencies: Diagnosis thanks to non invasive blood enzymatic and molecular studies

Glycogen storage disease (GSD) due to a deficient hepatic phosphorylase system defines a genetically heterogeneous group of disorders that mainly manifests in children. We investigated 45 unrelated children in whom a liver GSD VI or IX was suspected on the basis of clinical symptoms including hepatomegaly, increased serum transaminases, postprandial lactatemia and/or mild fasting hypoglycemia. Liver phosphorylase and phosphorylase b kinase activities studied in peripheral blood cells allowed to suspect diagnosis in 37 cases but was uninformative in 5. Sequencing of liver phosphorylase genes was useful to establish an accurate diagnosis. Causative mutations were found either in the PYGL (11 patients), PHKA2 (26 patients), PHKG2 (three patients) or in the PHKB (three patients) genes. Eleven novel disease causative mutations, five missense (p.N188K, p.D228Y, p.P382L, p.R491H, p.L500R) and six truncating mutations (c.501_502ins361pb, c.528+2T>C, c.856-29_c.1518+614del, c.1620+1G>C, p.E703del and c.2313-1G>T) were identified in the PYGL gene. Seventeen novel disease causative mutations, ten missense (p.A42P, p.Q95R, p.G131D, p.G131V, p.Q134R, p.G187R, p.G300V, p.G300A, p.C326Y, p.W820G) and seven truncating (c.537+5G>A, p.G396DfsX28, p.Q404X, p.N653X, p.L855PfsX87, and two large deletions) were identified in the PHKA2 gene. Four novel truncating mutations (p.R168X, p.Q287X, p.I268PfsX12 and c.272-1G>C) were identified in the PHKG2 gene and three (c.573_577del, p.R364X, c.2427+3A>G) in the PHKB gene. Patients with PHKG2 mutations evolved towards cirrhosis. Molecular analysis of GSD VI or IX genes allows to confirm diagnosis suspected on the basis of enzymatic analysis and to establish diagnosis and avoid liver biopsy when enzymatic studies are not informative in blood cells.

Acute but transient neurological deterioration revealing adult polyglucosan body disease.

Adult polyglucosan body disease (APBD) is a metabolic disorder usually caused by glycogen branching enzyme (GBE) deficiency. APBD associates progressive walking difficulties, bladder dysfunction and, in about 50% of the cases, cognitive decline. APBD is characterized by a recognizable leukodystrophy on brain MRI. We report here a novel presentation of this disease in a 35-year old woman who presented with an acute deterioration followed by an unexpected recovery. Enzymatic analysis displayed decreased GBE activity in leukocytes. Molecular analyses revealed that only one mutated allele was expressed, bearing a p.Arg515His mutation. This is the first observation reporting acute and reversible neurological symptoms in APBD. These findings emphasize the importance of searching GBE deficiency in patients presenting with a leukodystrophy and acute neurological symptoms mimicking a stroke, in the absence of cardiovascular risk factors.