ClinVar Genomic variation as it relates to human health

The IFT140 c.1648C>T variant is predicted to result in premature protein termination (p.Arg550*). This variant was reported in the heterozygous state in an individual with atypical autosomal dominant polycystic kidney disease (ADPKD) (Senum et al. 2022. PubMed ID: 34890546). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Nonsense variants in IFT140 are expected to be pathogenic for autosomal recessive and autosomal dominant IFT140-related disorders (see below). This variant is interpreted as pathogenic.

Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has been reported in two unrelated patients with presumed autosomal dominant cystic renal disease (PMID: 34890546); This variant is associated with the following publications: (PMID: 34890546)

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with retinitis pigmentosa 80 (MIM#617781), short-rib thoracic dysplasia 9 with or without polydactyly (MIM#266920) and cystic kidney disease (MONDO:0002473), IFT140-related (PMID: 34890546). (I) 0108 - This gene is associated with both recessive and dominant disease. Retinitis pigmentosa 80 (MIM#617781) and short-rib thoracic dysplasia 9 with or without polydactyly (MIM#266920) are inherited in an autosomal recessive manner, while cystic kidney disease (MONDO:0002473), IFT140-related is inherited in an autosomal dominant manner (OMIM, PMID: 34890546) . (I) 0112 - The dominant condition associated with this gene may have incomplete penetrance. Parents of children with short-rib thoracic dysplasia 9 with or without polydactyly, who carry a single pathogenic variant that has also previously been associated with the dominant cystic kidney disease phenotype, have been reported as unaffected (PMID: 34890546). However these parents weren't specifically assessed for cystic kidney disease. (I) 0201 - Variant is predicted to cause nonsense-mediated decay (NMD) and loss of protein (premature termination codon is located at least 54 nucleotides upstream of the final exon-exon junction). (SP) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0701 - Other NMD-predicted variants comparable to the one identified in this case have very strong previous evidence for pathogenicity (DECIPHER). These variants have been reported in families with later onset autosomal dominant polycystic kidney disease (PMID: 34890546) and autosomal recessive IFT140-related conditions (PMIDs: 22503633, 26968735). (SP) 0802 - This variant has moderate previous evidence of pathogenicity in unrelated individuals. This variant has been reported as pathogenic in ClinVar and has been observed in two individuals with autosomal dominant cystic kidney disease (PMID: 34890546). (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign

PM2, PS4_moderate, PVS1