5-132369824-G-A
Variant summary
Our verdict is Likely pathogenic. The variant received 6 ACMG points: 8P and 2B. PP5_Very_StrongBP4BS1_Supporting
The NM_003060.4(SLC22A5):c.-149G>A variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00266 in 988,154 control chromosomes in the GnomAD database, including 11 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Consequence
NM_003060.4 5_prime_UTR_premature_start_codon_gain
Scores
Clinical Significance
Conservation
Publications
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ACMG classification
Our verdict: Likely_pathogenic. The variant received 6 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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SLC22A5 | NM_003060.4 | c.-149G>A | 5_prime_UTR_premature_start_codon_gain_variant | Exon 1 of 10 | ENST00000245407.8 | NP_003051.1 | ||
SLC22A5 | NM_003060.4 | c.-149G>A | 5_prime_UTR_variant | Exon 1 of 10 | ENST00000245407.8 | NP_003051.1 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
SLC22A5 | ENST00000245407.8 | c.-149G>A | 5_prime_UTR_premature_start_codon_gain_variant | Exon 1 of 10 | 1 | NM_003060.4 | ENSP00000245407.3 | |||
SLC22A5 | ENST00000245407.8 | c.-149G>A | 5_prime_UTR_variant | Exon 1 of 10 | 1 | NM_003060.4 | ENSP00000245407.3 |
Frequencies
GnomAD3 genomes AF: 0.00141 AC: 215AN: 152164Hom.: 1 Cov.: 33 show subpopulations
GnomAD4 exome AF: 0.00289 AC: 2414AN: 835880Hom.: 10 Cov.: 11 AF XY: 0.00277 AC XY: 1166AN XY: 420334 show subpopulations
GnomAD4 genome AF: 0.00141 AC: 215AN: 152274Hom.: 1 Cov.: 33 AF XY: 0.00128 AC XY: 95AN XY: 74464 show subpopulations
ClinVar
Submissions by phenotype
Renal carnitine transport defect Pathogenic:9
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The c.-149G>A variant in the SLC22A5 gene has been previously reported in the homozygous or compound heterozygous state in >40 individuals with features of primary carnitine deficiency (Ferdinandusse et al., 2019). This variant also segregated with disease in several affected individuals from one family (Verbeeten et al., 2020). This variant has been described in association with a milder phenotype (Ferdinandusse et al., 2019). This variant has been identified in 171/68,006 European non-Finnish chromosomes (215/152,164 chromosomes overall), including 1 homozygous occurrence, by the Genome Aggregation Database (http://gnomad.broadinstitute.org/). This variant is present in ClinVar (Variation ID: VCV000025340.46). This variant occurs within the 5’ untranslated region (UTR) of SLC22A5. Functional studies demonstrated that this variant introduces a functional upstream out-of-frame translation initiation codon, which suppresses translation from the wild-type initiation codon and results in reduced protein levels and reduced carnitine transporter activity (Ferdinandusse et al., 2019). -
This variant occurs in a non-coding region of the SLC22A5 gene. It does not change the encoded amino acid sequence of the SLC22A5 protein. This variant is present in population databases (rs57262206, gnomAD 0.2%), and has an allele count higher than expected for a pathogenic variant. This variant has been observed in individuals with primary carnitine deficiency (PMID: 31187905). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 25340). Algorithms developed to predict the effect of variants on gene product structure and function are not available or were not evaluated for this variant. Experimental studies have shown that this variant affects SLC22A5 function (PMID: 31187905). For these reasons, this variant has been classified as Pathogenic. -
Variant summary: SLC22A5 c.-149G>A is located in the untranslated mRNA region upstream of the initiation codon. The variant allele was found at a frequency of 0.0014 in 150938 control chromosomes in the gnomAD v3.1.2 database, including 1 homozygote. This frequency is not higher than expected for a pathogenic variant in SLC22A5 causing Systemic Primary Carnitine Deficiency (0.0014 vs 0.0046), allowing no conclusion about variant significance. c.-149G>A has been reported to segregate with carnitine uptake defect in a large family where several affected members were homozygous for the variant of interest (Verbeeten_2020). The variant has also been reported in several other unrelated individuals (homozygous, compound heterozygous and heterozygous) affected with primary carnitine deficiency (Ferdinandusse_2019). Most of the affected patients showed a mild phenotype. Functional studies conducted in patient derived fibroblasts (from homozygous individuals) showed reduced Carnitine transport activity (Verbeeten_2020, Ferdinandusse_2019). Ferdinandusse et al also report that c.-149G>A introduces a functional upstream out-of-frame translation initiation codon and this codon suppresses translation from the wild-type AUG of SLC22A5, resulting in reduced OCTN2 protein levels and therefore, lower OCTN2 transport activity and carnitine deficiency in patients harboring this variant (Ferdinandusse_2019). Seven ClinVar submitters (evaluation after 2014) cite the variant as pathogenic (n=6) or uncertain significance (n=1). Based on the evidence outlined above, the variant was classified as pathogenic. -
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not provided Pathogenic:4
SLC22A5: PM3:Very Strong, PP1:Moderate, PS3:Moderate, PM2:Supporting -
Reported in the homozygous state and in the presence of a second pathogenic variant in individuals with primary carnitine deficiency (Ferdinandusse et al., 2019); Individuals homozygous for this variant had approximately 31% average carnitine transport activity in fibroblasts compared to controls (Ferdinandusse et al., 2019); In vitro functional studies demonstrate that c.-149G>A introduces an upstream out-of-frame translation initiation codon that causes reduced production of OCTN2 protein (Ferdinandusse et al., 2019); This variant is associated with the following publications: (PMID: 31187905, 31864849, 31980526) -
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PP1_strong, PS3, PS4 -
Inborn genetic diseases Pathogenic:1
The c.-149G>A alteration is located in the 5' untranslated region (5'UTR) of the SLC22A5 gene. This alteration consists of a G to A substitution 149 nucleotides upstream from the first translated codon. Based on data from gnomAD, the A allele has an overall frequency of 0.128% (40/31306) total alleles studied. The highest observed frequency was 0.238% (2/842) of Latino alleles. This variant has been identified in the homozygous state and in conjunction with other SLC22A5 variants in individuals with features consistent with systemic primary carnitine deficiency and segregated with disease in at least one family (Ferdinandusse, 2019; Verbeeten, 2020; Ziats, 2021). Functional studies indicated that the variant introduces a functional upstream outofframe translation initiation codon, which suppresses translation from the wildtype ATG of SLC22A5, resulting in lower transport activity. Based on the available evidence, this alteration is classified as pathogenic. -
SLC22A5-related disorder Pathogenic:1
The SLC22A5 c.-149G>A variant is located in the 5' untranslated region. This variant has been reported, in the homozygous or compound heterozygous state, in numerous individuals with primary carnitine deficiency (PCD) (Ferdinandusse et al. 2019. PubMed ID: 31187905; Verbeeten et al. 2020. PubMed ID: 31864849). It was found in in the homozygous and apparently compound heterozogous state in several individuals who were classified as having a likely benign form of PCD who were asymptomatic or only had mild symptoms, regardless of treatment. (Crefcoeur et al. 2023. PubMed ID: 37487700). The c.-149G>A variant was predicted to create a novel translation initiation codon upstream of the canonical AUG start codon, and in a functional assay using a luciferase reporter construct, the c.-149G>A variant was found to reduce luciferase activity to 11% of control (Ferdinandusse et al. 2019. PubMed ID: 31187905). Furthermore, carnitine transport activity was reduced in patient fibroblasts with the c.-149G>A variant (Ferdinandusse et al. 2019. PubMed ID: 31187905; Verbeeten et al. 2020. PubMed ID: 31864849). Based on these observations, we classify this variant as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at