rs201650281
Variant summary
Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PP3PP5_Very_Strong
The NM_005548.3(KARS1):c.599C>T(p.Pro200Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000159 in 1,613,970 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. P200P) has been classified as Likely benign.
Frequency
Consequence
NM_005548.3 missense
Scores
Clinical Significance
Conservation
Publications
- autosomal recessive nonsyndromic hearing loss 89Inheritance: AR Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), G2P
- leukoencephalopathy, progressive, infantile-onset, with or without deafnessInheritance: AR Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
- Charcot-Marie-Tooth disease recessive intermediate BInheritance: AR, Unknown Classification: SUPPORTIVE, LIMITED Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
- hearing loss, autosomal recessiveInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- nonsyndromic genetic hearing lossInheritance: AR Classification: LIMITED Submitted by: ClinGen
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ACMG classification
Our verdict: Likely_pathogenic. The variant received 9 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| KARS1 | NM_005548.3 | c.599C>T | p.Pro200Leu | missense_variant | Exon 5 of 14 | ENST00000302445.8 | NP_005539.1 | |
| KARS1 | NM_001130089.2 | c.683C>T | p.Pro228Leu | missense_variant | Exon 6 of 15 | NP_001123561.1 | ||
| KARS1 | NM_001378148.1 | c.131C>T | p.Pro44Leu | missense_variant | Exon 5 of 14 | NP_001365077.1 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000118 AC: 18AN: 152160Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000139 AC: 35AN: 251384 AF XY: 0.000140 show subpopulations
GnomAD4 exome AF: 0.000163 AC: 239AN: 1461810Hom.: 0 Cov.: 31 AF XY: 0.000173 AC XY: 126AN XY: 727216 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000118 AC: 18AN: 152160Hom.: 0 Cov.: 32 AF XY: 0.000121 AC XY: 9AN XY: 74324 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Pathogenic:4
KARS1: PM3:Very Strong, PM2, PS3:Supporting -
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This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 228 of the KARS protein (p.Pro228Leu). This variant is present in population databases (rs201650281, gnomAD 0.1%). This missense change has been observed in individuals with nonsyndromic deafness with mitochondrial features (PMID: 23596069, 30252186, 30369941, 31116475). ClinVar contains an entry for this variant (Variation ID: 224983). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt KARS protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects KARS function (PMID: 31116475). For these reasons, this variant has been classified as Pathogenic. -
Published in vitro functional studies demonstrate a strongly decreased aminoacylation activity compared with wild type KARS, which may result in decreased level of translation of the nuclear encoded lysine rich proteins belonging to the respiratory chain complex (Scheidecker et al., 2019); Associated with multiple oxidative phosphorylation deficiency in patient fibroblasts and the mitochondrial translation is specifically inhibited in patient fibroblasts expressing this mutant protein (Ruzzenente et al., 2018); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 25356970, 23596069, 30252186, 29875423, 29615062, 30709774, 30369941, 31116475, 34172899, 32319008, 33972171) -
KARS1-related disorder Pathogenic:3
PS3, PM3_Strong -
The KARS1 c.683C>T variant is predicted to result in the amino acid substitution p.Pro228Leu. This variant has been reported in the compound heterozygous state in at least two unrelated individuals with developmental delay, hypotonia, ophthalmoplegia, sensorineural deafness and other neurologic manifestations (Lieber et al. 2013. PubMed ID: 23596069; Ruzzenente et al. 2018. PubMed ID: 30252186). This variant was also described in the compound heterozygous state in an individual who presented with severe optic neuropathy (Scheidecker et al. 2019. PubMed ID: 31116475), as well as in the homozygous state in a patient who presented with features consistent with a suspected mitochondrial disorder, including lactic acidosis and hyperechogenic liver with ascites (Felhi et al. 2020. PubMed ID: 32319008). Lastly, this variant was described in the compound heterozygous state in an individual who presented with sensorineural deafness, psychomotor retardation, spasticity, and epilepsy (Theunissen et al. 2018. PubMed ID: 30369941). Functional studies using patient fibroblasts found a multiple oxidative phosphorylation deficiency due to impaired mitochondrial translation (Ruzzenente et al. 2018. PubMed ID: 30252186). In summary, the c.683C>T variant is categorized as pathogenic for autosomal recessive KARS1-related disorders. -
This individual was also found to have a paternally inherited heterozygous c.856_857insSVA variant in exon 7 of KARS1 (ENST00000319410). This alteration represents a mobile element SINE-R/VNTR (variable number of tandem repeat)/Alu (SVA). SVAs are active non-LTR retrotransposable elements that are intermediate in size relative to Alu and L1, and are likely to be transcribed by RNA polymerase II (PMID: 22364178). -
Leukoencephalopathy, progressive, infantile-onset, with or without deafness Pathogenic:2
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Abnormal pyramidal sign;C0393525:Progressive cerebellar ataxia;C0948163:Abnormal cerebral white matter morphology;C1865866:Congenital sensorineural hearing impairment;C3887709:Optic neuropathy Pathogenic:1
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Inborn genetic diseases Pathogenic:1
Overall WES conclusion for patient, including all identified alterations: UNCERTAIN: Alteration(s) of Uncertain Clinical Significance Detected -
Charcot-Marie-Tooth disease recessive intermediate B Pathogenic:1
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Deafness, congenital, and adult-onset progressive leukoencephalopathy Pathogenic:1
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KARS-related disorder Pathogenic:1
This variant has been previously reported as compound heterozygous with missense variants and frameshift variants, respectively, in children with mitochondrial respiratory chain complex deficiency features raging from hypotonia, global developmental delay, hearing loss, strabismus, ophthalmoplegia, dystonia to lactic acidosis, psychomotor retardation, spasticity and epilepsy (PMID: 23596069, 30252186, 30369941, 31116475). One ptatient's fibroblast demonstrated defective mitochondrial translation and OXPHOS biogenesis (PMID: 30252186), and biochemistry on another patient' muscle or fibroblasts showed decreased ATP production (PMID: 30369941). In addition, this alteration was shown to severely affect aminoacylation in-vitro (PMID: 31116475). It is present in the heterozygous state in the gnomAD population database at a frequency of 0.014% (40/282774) and thus is presumed to be rare. The majority of utilized in silico tools support a deleterious effect of the c.683C>T (p.Pro228Leu) variant on protein function. Based on the available evidence, the c.683C>T (p.Pro228Leu) variant is classified as Pathogenic. -
Hearing loss, autosomal recessive Pathogenic:1
The KARS1:NM_001130089.2:c.683C>T variant has well-established functional studies show damaging effect on the gene or gene product (PS3), is associated with a recessive disorder, detected in trans with a pathogenic variant, in homozygous state in affected cases (PM3), has extremely low frequency in gnomAD population databases (PM2), Cosegregation with disease in multiple affected family members in a gene definitively known to cause the disease (PP1). Here it was found in homozygosis in two affected siblings born from unrelated couple. -
LEUKOENCEPHALOPATHY, PROGRESSIVE, INFANTILE-ONSET, WITH DEAFNESS Pathogenic:1
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Autosomal recessive nonsyndromic hearing loss 89 Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at