ClinVar Genomic variation as it relates to human health

Variant summary: The TNNI3 c.273G>A (p.Ala91Ala) variant involves the alteration of a non-conserved nucleotide, resulting in a synonymous change. MutationTaster predicts a damaging outcome for this variant. 3/5 splice prediction tools predict no significant impact on normal splicing. ESE finder predicts that this variant may affect ESE sites at the locus. However, these predictions have yet to be confirmed by functional studies. This variant was found in 48/113142 control chromosomes from all ethnicities, but was predominantly observed in the African subpopulation at a frequency of 0.005606 (46/8206). This frequency is about 45 times the estimated maximal expected allele frequency of a pathogenic TNNI3 variant (0.000125), strongly suggesting this is likely a benign polymorphism found primarily in the populations of African origin. In addition, the variant was found to co-occur with a pathogenic DSP mutation (c.1dupA) in an internal LCA sample. Additionally, multiple clinical diagnostic laboratories/reputable databases have classified this variant as benign. The variant of interest has not, to our knowledge, been reported in affected individuals via publications nor evaluated for functional impact by in vivo/vitro studies. Taken together, this variant is classified as benign.

Ala91Ala in Exon 05 of TNNI3: This variant is not expected to have clinical sign ificance because it does not alter an amino acid residue, is not located within the splice consensus sequence and has been identified in 0.5% (14/2998) of Afric an American chromosomes from a broad population by the NHLBI Exome Sequencing Pr oject (http://evs.gs.washington.edu/EVS; dbSNP rs75491697).

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease.

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease.

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease.

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease.

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.