3-42686586-T-G
Variant summary
Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_152393.4(KLHL40):c.968T>G(p.Ile323Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000652 in 1,614,064 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Consequence
NM_152393.4 missense
Scores
Clinical Significance
Conservation
Publications
- nemaline myopathy 8Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics, G2P
- severe congenital nemaline myopathyInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Likely_benign. The variant received -2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes  0.000375  AC: 57AN: 152112Hom.:  0  Cov.: 33 show subpopulations 
GnomAD2 exomes  AF:  0.000406  AC: 102AN: 251450 AF XY:  0.000383   show subpopulations 
GnomAD4 exome  AF:  0.000681  AC: 995AN: 1461834Hom.:  0  Cov.: 30 AF XY:  0.000650  AC XY: 473AN XY: 727220 show subpopulations 
Age Distribution
GnomAD4 genome  0.000374  AC: 57AN: 152230Hom.:  0  Cov.: 33 AF XY:  0.000349  AC XY: 26AN XY: 74424 show subpopulations 
Age Distribution
ClinVar
Submissions by phenotype
not provided    Uncertain:3 
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In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
The KLHL40 p.Ile323Ser variant was not identified in the literature but was identified in dbSNP (ID: rs146161469) and ClinVar (classified as uncertain significance by Invitae for Nemaline myopathy 8 and GeneDx). The variant was identified in control databases in 108 of 282838 chromosomes at a frequency of 0.0003818 increasing the likelihood this could be a low frequency benign variant (Genome Aggregation Database March 6, 2019, v2.1.1). The variant was observed in the following populations: European (non-Finnish) in 96 of 129144 chromosomes (freq: 0.000743), Other in 4 of 7226 chromosomes (freq: 0.000554), European (Finnish) in 3 of 25124 chromosomes (freq: 0.000119), Latino in 4 of 35440 chromosomes (freq: 0.000113) and African in 1 of 24966 chromosomes (freq: 0.00004), but was not observed in the Ashkenazi Jewish, East Asian, or South Asian populations. Although the p.Ile323 residue is not conserved in mammals and other organisms, computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the variant may impact the protein. The variant occurs outside of the splicing consensus sequence and 1 of 4 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) predict a greater than 10% difference in splicing; this is not very predictive of pathogenicity. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -
not specified    Uncertain:1 
Variant summary: KLHL40 c.968T>G (p.Ile323Ser) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00041 in 251450 control chromosomes (gnomAD). To our knowledge, no occurrence of c.968T>G in individuals affected with Nemaline Myopathy 8 and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 279825). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Nemaline myopathy 8    Uncertain:1 
This sequence change replaces isoleucine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 323 of the KLHL40 protein (p.Ile323Ser). This variant is present in population databases (rs146161469, gnomAD 0.07%). This variant has not been reported in the literature in individuals affected with KLHL40-related conditions. ClinVar contains an entry for this variant (Variation ID: 279825). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on KLHL40 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Computational scores
Source: 
Splicing
 Find out detailed SpliceAI scores and Pangolin per-transcript scores at