ClinVar Miner

Submissions for variant NM_054012.4(ASS1):c.892del (p.Glu298fs) (rs770362721)

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Total submissions: 6
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Submitter RCV SCV Clinical significance Condition Last evaluated Review status Method Comment
Counsyl RCV000169181 SCV000220418 likely pathogenic Citrullinemia type I 2014-06-16 criteria provided, single submitter literature only
Women's Health and Genetics/Laboratory Corporation of America, LabCorp RCV000169181 SCV000694166 pathogenic Citrullinemia type I 2016-05-04 criteria provided, single submitter clinical testing Variant summary: The c.892delG variant is predicted to cause a frameshift, which alters the proteins amino acid sequence beginning at position 298 and leads to a premature termination codon 17 amino acids downstream. It is predicted to cause a truncated or absent ASS1 protein, which is a commonly known mechanism for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (e.g.R389Qfs). One in-silico tool predicts damaging outcome for this variant. This variant is found in 1/121396 control chromosomes at a frequency of 0.0000082, which does not exceed maximal expected frequency of a pathogenic allele (0.0040825). This variant has been reported in at least two affected individuals. In addition, one clinical laboratory classified this variant as likely pathogenic, without evidence to independently evaluate. Taken together, this variant was classified as pathogenic.
Invitae RCV001376598 SCV000818931 pathogenic Citrullinemia 2020-10-08 criteria provided, single submitter clinical testing This sequence change creates a premature translational stop signal (p.Glu298Argfs*18) in the ASS1 gene. It is expected to result in an absent or disrupted protein product. This variant is present in population databases (rs770362721, ExAC 0.001%). This variant has been reported in combination with another ASS1 variant in individuals affected with citrullinemia type I (PMID: 25433810, 15863597). ClinVar contains an entry for this variant (Variation ID: 188832). Loss-of-function variants in ASS1 are known to be pathogenic (PMID: 18473344, 19006241). For these reasons, this variant has been classified as Pathogenic.
Illumina Clinical Services Laboratory,Illumina RCV000169181 SCV000915271 pathogenic Citrullinemia type I 2017-09-18 criteria provided, single submitter clinical testing The ASS1 c.892delG (p.Glu298ArgfsTer18) variant results in a frameshift and is predicted to result in premature termination of the protein. The p.Glu298ArgfsTer18 variant has been reported in three studies in which it has been found in a compound heterozygous state in four individuals with citrullinemia including two individuals with a missense variant on the second allele and two individuals with another frameshift variant on the second allele (Enns et al. 2005; Martín-Hernández et al. 2014; Diez-Fernandez et al. 2017). One of the individuals with two frameshift variants presented with neonatal onset of neurological damage (Martín-Hernández et al. 2014). The other individual with two frameshift variants also presented as a neonate with elevated citrulline levels and hyperammonemia and died aged five days (Diez-Fernandez et al. 2017). Control data are unavailable for this variant, which is reported at a frequency of 0.000016 in the European (non-Finnish) population of the Genome Aggregation Database but this is based on two alleles in a region of good sequence coverage, so the variant is presumed to be rare. Analysis in skin fibroblasts from a patient initially presenting with neurological symptoms post-partum showed undetectable argininosuccinate synthetase activity. A radiolabeled 14C-citrulline/3H-leucine protein incorporation assay confirmed argininosuccinate synthetase deficiency (Enns et al. 2005). Plasma clinical chemistry in this patient show elevated plasma citrulline levels and mild hyperammonemia (Enns et al. 2005). Based on the evidence and the potential impact of frameshift variants, the p.Glu298ArgfsTer18 variant is classified as pathogenic for citrullinemia. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population.
Baylor Genetics RCV000169181 SCV001163593 pathogenic Citrullinemia type I criteria provided, single submitter clinical testing
Natera, Inc. RCV000169181 SCV001453091 pathogenic Citrullinemia type I 2020-09-16 no assertion criteria provided clinical testing

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