Dataset Information

Mildly elevated succinylacetone and normal liver function in compound heterozygotes with pathogenic and pseudodeficient FAH alleles.

ABSTRACT: Background:A high level of succinylacetone (SA) in blood is a sensitive, specific marker for the screening and diagnosis of hepatorenal tyrosinemia (HT1, MIM 276700). HT1 is caused by mutations in the FAH gene, resulting in deficiency of fumarylacetoacetate hydrolase. HT1 newborns are usually clinically asymptomatic, but have coagulation abnormalities revealing liver dysfunction. Treatment with nitisinone (NTBC) plus dietary restriction of tyrosine and phenylalanine prevents the complications of HT1. Observations:Two newborns screened positive for SA but had normal coagulation testing. Plasma and urine SA levels were 3-5 fold above the reference range but were markedly lower than in typical HT1. Neither individual received nitisinone or dietary therapy. They remain clinically normal, currently aged 9 and 15 years. Each was a compound heterozygote, having a splicing variant in trans with a prevalent "pseudodeficient" FAH allele, c.1021C > T (p.Arg341Trp), which confers partial FAH activity. All newborns identified with mild hypersuccinylacetonemia in Québec have had genetic deficiencies of tyrosine degradation: either deficiency of the enzyme preceding FAH, maleylacetoacetate isomerase, or partial deficiency of FAH itself. Conclusion:Compound heterozygotes for c.1021C > T (p.Arg341Trp) and a severely deficient FAH allele have mild hypersuccinylacetonemia and to date they have remained asymptomatic without treatment. It is important to determine the long term outcome of such individuals.

SUBMITTER: Yang H

PROVIDER: S-EPMC5758842 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Mildly elevated succinylacetone and normal liver function in compound heterozygotes with pathogenic and pseudodeficient <i>FAH</i> alleles.

Yang Hao H Rossignol Francis F Cyr Denis D Laframboise Rachel R Wang Shu Pei SP Soucy Jean-François JF Berthier Marie-Thérèse MT Giguère Yves Y Waters Paula J PJ Mitchell Grant A GA

Molecular genetics and metabolism reports 20171227

<h4>Background</h4>A high level of succinylacetone (SA) in blood is a sensitive, specific marker for the screening and diagnosis of hepatorenal tyrosinemia (HT1, MIM 276700). HT1 is caused by mutations in the <i>FAH</i> gene, resulting in deficiency of fumarylacetoacetate hydrolase. HT1 newborns are usually clinically asymptomatic, but have coagulation abnormalities revealing liver dysfunction. Treatment with nitisinone (NTBC) plus dietary restriction of tyrosine and phenylalanine prevents the c ...[more]

PMID: 29326876

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Project description:Previous studies of small cohorts have implicated several circulating cytokines with progression of chronic hepatitis B (CHB). However, to date there have been no reliable biomarkers for assessing histological liver damage in CHB patients with normal or mildly elevated alanine aminotransferase (ALT). The aim of the present study was to investigate the association between circulating cytokines and histological liver damage in a large cohort. Also, this study was designed to assess the utility of circulating cytokines in diagnosing liver inflammation and fibrosis in CHB patients with ALT less than 2 times the upper limit of normal range (ULN). A total of 227 CHB patients were prospectively enrolled. All patients underwent liver biopsy and staging by Ishak system. Patients with at least moderate inflammation showed significantly higher levels of CXCL-11, CXCL-10, and interleukin (IL)-2 receptor (R) than patients with less than moderate inflammation (P < 0.001). Patients with significant fibrosis had higher levels of IL-8 (P = 0.027), transforming growth factor alpha (TGF-α) (P = 0.011), IL-2R (P = 0.002), and CXCL-11 (P = 0.032) than the group without significant fibrosis. In addition, 31.8% and 29.1% of 151 patients with ALT < 2 × ULN had at least moderate inflammation and significant fibrosis, respectively. Multivariate analysis demonstrated that CXCL-11 was independently associated with at least moderate inflammation, and TGF-α and IL-2R independently correlated with significant fibrosis in patients with ALT < 2 × ULN. Based on certain cytokines and clinical parameters, an inflammation-index and fib-index were developed, which showed areas under the receiver operating characteristics curve (AUROC) of 0.75 (95% CI 0.66-0.84) for at least moderate inflammation and 0.82 (95% CI 0.75-0.90) for significant fibrosis, correspondingly. Compared to existing scores, fib-index was significantly superior to aspartate aminotransferase (AST) to platelet ratio index (APRI) and FIB-4 score for significant fibrosis. In conclusion, CXCL-11 was independently associated with at least moderate inflammation, whereas IL-2R and TGF-α were independent indicators of significant fibrosis in both, total CHB patients and patients with normal or mildly elevated ALT. An IL-2R and TGF-α based score (fib-index) was superior to APRI and FIB-4 for the diagnosis of significant fibrosis in patients with normal or mildly elevated ALT.

Dataset Information

Mildly elevated succinylacetone and normal liver function in compound heterozygotes with pathogenic and pseudodeficient FAH alleles.

Publications

Mildly elevated succinylacetone and normal liver function in compound heterozygotes with pathogenic and pseudodeficient <i>FAH</i> alleles.

Similar Datasets

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