These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Hypersuccinylacetonaemia and normal liver function in maleylacetoacetate isomerase deficiency.
    Author: Yang H, Al-Hertani W, Cyr D, Laframboise R, Parizeault G, Wang SP, Rossignol F, Berthier MT, Giguère Y, Waters PJ, Mitchell GA, Québec NTBC Study Group.
    Journal: J Med Genet; 2017 Apr; 54(4):241-247. PubMed ID: 27876694.
    Abstract:
    BACKGROUND: A high level of succinylacetone (SA) in blood is a sensitive, specific newborn screening marker for hepatorenal tyrosinemia type 1 (HT1, MIM 276700) caused by deficiency of fumarylacetoacetate hydrolase (FAH). Newborns with HT1 are usually clinically asymptomatic but show liver dysfunction with coagulation abnormalities (prolonged prothrombin time and/or high international normalised ratio). Early treatment with nitisinone (NTBC) plus dietary restriction of tyrosine and phenylalanine prevents the complications of severe liver disease and neurological crises. METHODS AND RESULTS: Six newborns referred for hypersuccinylacetonaemia but who had normal coagulation testing on initial evaluation had sequence variants in the GSTZ1 gene, encoding maleylacetoacetate isomerase (MAAI), the enzyme preceding FAH in tyrosine degradation. Initial plasma SA levels ranged from 233 to 1282 nmol/L, greater than normal (<24 nmol/L) but less than the initial values of patients with HT1 (16 944-74 377 nmol/L, n=15). Four individuals were homozygous for c.449C>T (p.Ala150Val). One was compound heterozygous for c.259C>T (p.Arg87Ter) and an intronic sequence variant. In one, a single heterozygous GSTZ1 sequence variant was identified, c.295G>A (p.Val99Met). Bacterial expression of p.Ala150Val and p.Val99Met revealed low MAAI activity. The six individuals with mild hypersuccinylacetonaemia (MHSA) were not treated with diet or nitisinone. Their clinical course has been normal for up to 13 years. CONCLUSIONS: MHSA can be caused by sequence variants in GSTZ1. Such individuals have thus far remained asymptomatic despite receiving no specific treatment.
    [Abstract] [Full Text] [Related] [New Search]