{{Rsnum
|rsid=13225917
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
|Chromosome=7
|Orientation=plus
|Gene=TTC26
|position=139166872
|Gene_s=TTC26
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;G)
| geno3=(G;G)
| CEU | 0.0 | 1.8 | 98.2
| HCB | 0.0 | 0.0 | 100.0
| JPT | 0.0 | 2.8 | 97.2
| YRI | 0.0 | 2.1 | 97.9
| ASW | 0.0 | 0.0 | 0.0
| CHB | 0.0 | 0.0 | 100.0
| CHD | 0.0 | 0.9 | 99.1
| GIH | 0.0 | 1.0 | 99.0
| LWK | 0.0 | 1.8 | 98.2
| MEX | 0.0 | 3.6 | 96.4
| MKK | 0.0 | 0.6 | 99.4
| TSI | 0.0 | 1.0 | 99.0
| HapMapRevision=28
}}
[[rs13225917]] represents a relatively rare SNP tested by the [[23andMe]] v3 chip. Due to its rarity, its effects have not and likely won't be determined through [[GWAS]] surveys. In [[HapMap]] populations, it's most common among Mexicans and Japanese occurring on the dominant European haplotype, and no homozygous A-allele carriers exist in [[HapMap]], [[OpenSNP]] or 1000 Genomes, though this might be due to the overall rarity of the [[rs13225917]](A) allele. The mutation causes an aspartate (D) to asparagine (N) change at position 310 (D310N, p.Asp310Asn) in the Tetratricopeptide repeat protein 26 ([[TTC26]]), which might (or might not) result in a damaging missense variant. The protein is IFT complex B protein, also known as [[DYF13]] in nematodes, and it has a proposed function-dependent name of [[IFT56]].

[[TTC26]] is thought to play a critical role in ciliogenesis and normal cilia (cellular "hairs") function, as determined by protein similarity, and it is highly conserved between ciliated species studied. In studies on Zebrafish, disabling the gene prevented normal development of photoreceptor sensory and other cilia. The protein is necessary for assembly of full length cilia, although the effect (if any) of [[rs13225917]] on its functioning has not been determined. One publication {{PMID|22718903}} speculates that this protein may play a role in Inherited Retinal Degeneration and so screening for TTC26 mutations in human [[ciliopathy|ciliopathies]] could be warranted, but to date there is no evidence supporting [[rs13225917]] as a mutation of any consequence.

{{PMID|24596149}} TTC26/DYF13 is an intraflagellar transport protein required for transport of motility-related proteins into flagella.

{{PMID|22718903}} Knockdown of ttc26 disrupts ciliogenesis of the photoreceptor cells and the pronephros in zebrafish.

{{PMID|10517866}} The tetratricopeptide repeat: a structural motif mediating protein-protein interactions.

{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | FTDNA2}}
{{on chip | FTDNA}}
{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}