{{Rsnum
|rsid=75527207
|Gene=CFTR
|Chromosome=7
|position=117587806
|Orientation=plus
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|Gene_s=CFTR
}}. 

Known primarily as G551D (although sometimes also called G511D) and also known as [[i4000305]] by 23andMe, [[rs75527207]] is a rare variant in the cystic fibrosis [[CFTR]] gene is thought to be present in ~1,200 patients in the US. The risk allele is [[rs75527207]](A). G551D is termed a 'gating mutant', and is considered to be a somewhat different class of cystic fibrosis mutation compared to variants that lead to misfolded proteins. 

Like almost all cystic fibrosis variants, individuals must inherit two defective CFTR alleles to manifest the disease; since G551D is ~20 times rarer than the most common CFTR variant, deltaF508, patients carrying one G551D variant are likely to be compound heterozygotes harboring an additional CFTR variant.

In early 2012, the biotech company Vertex Pharmaceutics received FDA approval to sell the drug [[Kalydeco]] ([[ivacaftor]]) to G551D [[cystic fibrosis]] patients over the age of 6. In phase 3 trials, Kalydeco increased lung function by 10% (in 161 patients) compared to placebo, and showed improvements in weight gain along with reductions in cough and sputum production.{{doi|10.1038/nbt0312-201a}}

See also: OMIM [http://omim.org/entry/602421#0122 602421.0013]

{{omim
|id=602421
|rsnum=75527207
|variant=0013
}}{{ClinVar
|rsid=75527207
|Reversed=0
|FwdREF=G
|FwdALT=A
|REF=G
|ALT=A
|RSPOS=117227860
|CHROM=7
|dbSNPBuildID=131
|SSR=0
|SAO=1
|VP=0x050268000000040402110100
|GENEINFO=CFTR:1080
|GENE_NAME=CFTR
|GENE_ID=1080
|WGT=0
|VC=SNV
|CLNALLE=1
|CLNHGVS=NC_000007.13:g.117227860G>A
|CLNSRC=CFTR2; GTR; OMIM Allelic Variant
|CLNORIGIN=1
|CLNSRCID=G551D; GTR000074114; GTR000257096; GTR000500233; 602421.0013
|CLNSIG=5
|CLNCUI=C0010674
|CLNDBN=Cystic fibrosis
|Disease=Cystic fibrosis
|CLNACC=RCV000007540.6
|Tags=PM;PMC;S3D;VLD;HD;OTHERKG;LSD;OM
|CLNDSDB=GeneReviews:MedGen:OMIM:Orphanet:SNOMED_CT
|CLNDSDBID=NBK1250:C0010674:219700:586:190905008
}}{{PMID Auto
|PMID=7522329
|Title=Phosphatase inhibitors activate normal and defective CFTR chloride channels.
|OA=1
}}

{{PMID Auto
|PMID=7599637
|Title=A single-tube multiplex system for the simultaneous detection of 10 common cystic fibrosis mutations.
}}

{{PMID Auto
|PMID=8166795
|Title=Correlation between genotype and phenotype in patients with cystic fibrosis. The Cystic Fibrosis Genotype-Phenotype Consortium.
}}

{{PMID Auto
|PMID=10341008
|Title=Screening for cystic fibrosis transmembrane conductance regulator gene mutations in men included in an intracytoplasmic sperm injection programme.
}}

{{PMID Auto
|PMID=10653141
|Title=Study of mutant and polyvariant mutant CFTR genes in patients with congenital absence of the vas deferens.
}}

{{PMID Auto
|PMID=12767731
|Title=Effect of genotype on phenotype and mortality in cystic fibrosis: a retrospective cohort study.
}}