Aminoacidopathy
Gene: GSTZ1
PMID: 27876694 Six newborns with hypersuccinylacetonaemia but normal coagulation testing on initial evaluation. 4 probands homozygous for the recurrent variant c.449C>T (p.Ala150Val), 1 compound heterozygous for c.259C>T (p.Arg87Ter) and c.68-12G>A, and the last only had a single hit c.295G>A (p.Val99Met). Bacterial expression of p.Ala150Val and p.Val99Met showed reduced enzyme activity. Suggested to be a benign biochemical finding as in all patients clinical course has been normal for up to 13 years.
PMID: 38535121 proband with elevated succinylacetone in DBS on newborn screening. at 2 weeks old this had normalized but traces of succinylacetone were found in urine. Found to have a homozygous variant c.136−2A>G, the mother was heterozygous while the father was homozygous (variant has 2 hets no homs in gnomad). The father was 32yrs old with no medical complaints and a biochemical work up was normal. the proband had microcephaly and short stature but otherwise normal development.
PMID: 41009955 2 probands with elevated succinylacetone and normal tyrosine levels on NBS. Patient 1 compound heterozygous for c.68-12G>A and c.464_471delinsCTGGG (in frame), patient 2 compound heterozygous for c.68-12G>A and c.295G>A, p.(Val99Met). Patient 1 at 4 yrs of age had normal tyrosine, liver and kidney function tests, and regular development. patient 2 at 2yrs old had good clinical conditions, regular growth and development. RNA seq of the c.68-12G>A variant showed it lead to the out of frame 10bp retention of the intron. Val99Met has 1170 hets and 4 homs in gnomad, as this condition appears to be clinically benign this is not a concern.
Currently rated as moderate by ClinGen, the review does not include the most recent paperCreated: 10 Oct 2025, 10:02 a.m. | Last Modified: 10 Oct 2025, 10:02 a.m.
Panel Version: 1.135
      Mode of inheritance
      BIALLELIC, autosomal or pseudoautosomal
    
      Phenotypes
      Maleylacetoacetate isomerase deficiency MIM#617596
    
Publications
Classified Moderate by ClinGen Aminoacidopathy GCEP on 09/09/2022 -https://search.clinicalgenome.org/CCID:005017
6 probands have been reported with mild hypersuccinylacetonaemia (MHSA). The reported individuals remained well without receiving any treatment or change in diet.
Sources: ClinGenCreated: 7 Jun 2024, 9:43 a.m.
      Mode of inheritance
      BIALLELIC, autosomal or pseudoautosomal
    
      Phenotypes
      maleylacetoacetate isomerase deficiency MONDO:0060527
    
Publications
Publications for gene: GSTZ1 were set to 27876694
Gene: gstz1 has been classified as Green List (High Evidence).
Gene: gstz1 has been classified as Red List (Low Evidence).
Gene: gstz1 has been classified as Red List (Low Evidence).
gene: GSTZ1 was added gene: GSTZ1 was added to Aminoacidopathy. Sources: ClinGen Mode of inheritance for gene: GSTZ1 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: GSTZ1 were set to 27876694 Phenotypes for gene: GSTZ1 were set to maleylacetoacetate isomerase deficiency MONDO:0060527 Review for gene: GSTZ1 was set to RED