Skip to content
Use your HSA or FSA funds

Gene

ASS1

argininosuccinate synthase 1

Summary

Cytogenetic location
9q34.11
Coordinates
Chromosome 9: 130,444,961–130,501,274 (GRCh38)
Exons
15 exons across 56.3 kb
Protein
412 amino acids
Inheritance
Autosomal recessive
Also known as
CTLN1
Previous symbols
ASS
MANE Select transcript
ENST00000352480.10NM_054012.4
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated reports relevant to this gene

  • Citrullinemia

    • Autosomal recessive

      Citrullinemia is an autosomal recessively inherited disorder of urea cycle metabolism and ammonia detoxification characterized by elevated concentrations of serum citrulline and ammonia. The disease presents with a large range of manifestations including neonatal hyperammonemic encephalopathy with lethargy, seizures and coma; hepatic dysfunction in all age groups; episodes of hyperammonemia and neuropsychiatric symptoms in children or adults, or, can be asymptomatic in some cases (detected in newborn screening programs). Citrullinemia is divided into two main groups that are encoded by different genes: citrullinemia type I (comprised of acute neonatal citrullinemia type I and adult-onset citrullinemia type I) and citrin deficiency (comprised of adult-onset citrullinemia type II and neonatal intrahepatic cholestasis due to citrin deficiency).

      • ClinGen rates the link definitive
      • 6 GenCC submitters rate it definitive or strong

  • Urea Cycle Disorder

    • A genetic inborn error of metabolism characterized by the deficiency of one of the enzymes necessary for the urea cycle. It results in accumulation of ammonia in the body.

      • ClinGen rates the link definitive
      • 6 GenCC submitters rate it definitive or strong
      What knowing changes

      Nitrogen scavenger therapy (sodium benzoate, glycerol phenylbutyrate/Ravicti); protein-restricted diet with essential amino acid supplementation; emergency hyperammonemia protocols; liver transplantation (curative); mRNA therapy trials for OTC; carglumic acid for NAGS deficiency

Inheritance

Autosomal recessive
It takes a changed copy from each parent. With one, you are a carrier and usually unaffected; when both parents are carriers, each child has a one-in-four chance of inheriting two.

How ASS1 is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
Chromosome 9, with a bracket where ASS1 sits. ASS1 and 11 genes near it on chromosome 9, from 129,973,118 to 130,973,117.Chromosome 99q34.11p24.3p24.2p24.1p23p22.3p22.2p22.1p21.3p21.2p21.1p13.3p13.2p13.1p12p11.2p11.1q11q12q13q21.11q21.12q21.13q21.2q21.31q21.32q21.33q22.1q22.2q22.31q22.32q22.33q31.1q31.2q31.3q32q33.1q33.2q33.3q34.11q34.12q34.13q34.2q34.3130 Mb130.2 Mb130.4 Mb130.6 Mb130.8 MbFNBP1: 129,887,179–130,043,243, reverse strandFNBP1GPR107: 130,053,426–130,140,169, forward strandGPR107NCS1: 130,172,315–130,237,737, forward strandNCS1HMCN2: 130,265,746–130,434,123, forward strandHMCN2ASS1: 130,444,961–130,501,274, forward strandASS1FUBP3: 130,578,965–130,638,354, forward strandFUBP3PRDM12: 130,664,594–130,682,986, forward strandPRDM12EXOSC2: 130,693,721–130,707,608, forward strandEXOSC2ABL1: 130,713,043–130,887,675, forward strandABL1: 130,713,626–130,713,724, forward strandQRFP: 130,892,707–130,896,812, reverse strandQRFPFIBCD1: 130,900,194–130,941,232, reverse strandFIBCD1Diagram of ASS1: 15 exons on the forward strand of chromosome 9Exon 2: 8 known disease-causing sitesExon 3: 8 known disease-causing sitesExon 4: 26 known disease-causing sitesExon 5: 11 known disease-causing sitesExon 6: 13 known disease-causing sitesExon 7: 6 known disease-causing sitesExon 8: 1 known disease-causing siteExon 9: 8 known disease-causing sitesExon 10: 7 known disease-causing sitesExon 11: 15 known disease-causing sitesExon 12: 27 known disease-causing sitesExon 13: 24 known disease-causing sitesExon 14: 7 known disease-causing sitesExon 1: 130,444,961–130,444,995, 35 basesExon 2: 130,452,224–130,452,333, 110 basesExon 3: 130,454,305–130,454,373, 69 basesExon 4: 130,458,401–130,458,589, 189 basesExon 5: 130,464,111–130,464,167, 57 basesExon 6: 130,466,725–130,466,799, 75 basesExon 7: 130,470,834–130,470,904, 71 basesExon 8: 130,471,485–130,471,515, 31 basesExon 9: 130,476,871–130,476,961, 91 basesExon 10: 130,479,716–130,479,800, 85 basesExon 11: 130,480,385–130,480,449, 65 basesExon 12: 130,489,333–130,489,464, 132 basesExon 13: 130,494,867–130,495,023, 157 basesExon 14: 130,499,505–130,499,570, 66 basesExon 15: 130,500,976–130,501,274, 299 bases12468101214155′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 1.5 kb of the gene's 56.3 kb; 1,239 of those bases code for the protein.

How a genome test reads ASS1

197

positions in ASS1 where ClinVar classes a change as pathogenic or likely pathogenic

None of them falls in a region short reads find hard.

A whole genome covers all 56.3 kb of ASS1, introns included, not only the 1.5 kb of exons.

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
  • The ACMG secondary findings list, SF v3.2.
  • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

Cite this page

APA

Dante Labs. (n.d.). ASS1 gene: argininosuccinate synthase 1. Retrieved 16 October 2026, from https://dantelabs.com/genes/ass1

Vancouver

Dante Labs. ASS1 gene: argininosuccinate synthase 1 [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/ass1

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test