OMIA:000394-9031 : Frizzle, KRT6A-related in Gallus gallus (chicken)

Categories: Integument (skin) phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 615726 (trait) , 148041 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal incomplete dominant

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2012

Cross-species summary: The KRT6A gene was named KRT75 in an earlier chicken genome assembly and the phene was therefore renamed from 'Frizzle, KRT75-related' to 'Frizzle, KRT6A-related' [13/1/1022]

Species-specific name: Also called Frizzling

Species-specific symbol: F

History: Somes (1990) cites Lind (1963) who mentions this trait being described as early as 1600, by Aldrovandi.

Inheritance: Davenport (1906), Hutt (1930) and Landauer and Dunn (1930) all provided evidence for single-locus autosomal incompletely dominant inheritance (Somes, 1990).

Mapping: Using a genome-wide scan of 45 birds in 5 families with 2678 SNPs, Ng et al. (2012) linkage-mapped the Frizzle locus to the linkage group E22C19W28_E50C23 on chromosome E22. From the chicken genome assembly, it was evident that this region contains a cluster of keratin genes.

Molecular basis: As reported by Ng et al. (2012): "Sequence analyses of the keratin gene cluster identified a 69 bp in-frame deletion in a conserved region of KRT75, an α-keratin gene. Retroviral-mediated expression of the mutated F cDNA in the wild-type rectrix qualitatively changed the bending of the rachis with some features of frizzle feathers including irregular kinks, severe bending near their distal ends, and substantially higher variations among samples in comparison to normal feathers. These results confirmed KRT75 as the F gene." The gene annotated as KRT 75 based on Galgal 3 in the Ng et al. (2012) PLOS Genetics paper is currently annotated as KRT6A based on Galgal 6. Dong et al. (2018) identified a variant in a different keratin gene (KRT75L4) causing a similar phenotype - see OMIA 002486-9031 : Frizzle, KRT75L4-related in Gallus gallus for details.

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
KRT6A keratin 6A Gallus gallus 34 NC_052565.1 (2048044..2053178) KRT6A Homologene, Ensembl , NCBI gene


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WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
662 Frizzle KRT6A deletion, gross (>20) Naturally occurring variant GRCg6a 33 g.5251413_5251496del p.(V311_K333del) NM_001001313.2; NP_001001313.2; published as a 84bp deletion that covers positions −24 of exon 5 to +59 of intron 5 of KRT6A (called KRT75 in an earlier genome assembly); the deletion activates a cryptic splice site resulting in a 69 bp in-frame deletion in mRNA after splicing and a deletion of 23-amino acids (position 311–333) 2012 22829773

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2022). OMIA:000394-9031: Online Mendelian Inheritance in Animals (OMIA) [dataset].


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.

2023 Chuang, T.C., Cheng, J.W., Chuong, C.M., Juan, W.T. :
Autofluorescence microscopy as a non-invasive probe to characterize the complex mechanical properties of keratin-based integumentary organs: A feather paradigm. Chin J Phys 86:561-571, 2023. Pubmed reference: 38370512. DOI: 10.1016/j.cjph.2023.10.017.
2022 Chen, B., Xi, S., El-Senousey, H.A.K., Zhou, M., Cheng, D., Chen, K., Wan, L., Xiong, T., Liao, M., Liu, S., Mao, H. :
Deletion in KRT75L4 linked to frizzle feather in Xiushui Yellow chickens. Anim Genet 53:101-107, 2022. Pubmed reference: 34904261. DOI: 10.1111/age.13158.
Fathi, M.M., Galal, A., Radwan, L.M., Abou-Emera, O.K., Al-Homidan, I.H. :
Using major genes to mitigate the deleterious effects of heat stress in poultry: an updated review. Poult Sci 101:102157, 2022. Pubmed reference: 36167017. DOI: 10.1016/j.psj.2022.102157.
2021 Ballantyne, M., Woodcock, M., Doddamani, D., Hu, T., Taylor, L., Hawken, R.J., McGrew, M.J. :
Direct allele introgression into pure chicken breeds using Sire Dam Surrogate (SDS) mating. Nat Commun 12:659, 2021. Pubmed reference: 33510156. DOI: 10.1038/s41467-020-20812-x.
2018 Dong, J., He, C., Wang, Z., Li, Y., Li, S., Tao, L., Chen, J., Li, D., Yang, F., Li, N., Zhang, Q., Zhang, L., Wang, G., Akinyemi, F., Meng, H., Du, B. :
A novel deletion in KRT75L4 mediates the frizzle trait in a Chinese indigenous chicken. Genet Sel Evol 50:68, 2018. Pubmed reference: 30572816. DOI: 10.1186/s12711-018-0441-7.
2012 Ng, C.S., Wu, P., Foley, J., Foley, A., McDonald, M.L., Juan, W.T., Huang, C.J., Lai, Y.T., Lo, W.S., Chen, C.F., Leal, S.M., Zhang, H., Widelitz, R.B., Patel, P.I., Li, W.H., Chuong, C.M. :
The chicken frizzle feather is due to an α-keratin (KRT75) mutation that causes a defective rachis. PLoS Genet 8:e1002748, 2012. Pubmed reference: 22829773. DOI: 10.1371/journal.pgen.1002748.
2011 Adeleke, MA., Peters, SO., Ozoje, MO., Ikeobi, CO., Bamgbose, AM., Adebambo, OA. :
Growth performance of Nigerian local chickens in crosses involving an exotic broiler breeder. Trop Anim Health Prod 43:643-50, 2011. Pubmed reference: 21088891. DOI: 10.1007/s11250-010-9747-3.
Peters, SO., Gunn, HH., Imumorin, IG., Agaviezor, BO., Ikeobi, CO. :
Haematological studies on frizzled and naked neck genotypes of Nigerian native chickens. Trop Anim Health Prod 43:631-8, 2011. Pubmed reference: 21107909. DOI: 10.1007/s11250-010-9743-7.
2010 Magothe, TM., Muhuyi, WB., Kahi, AK. :
Influence of major genes for crested-head, frizzle-feather and naked-neck on body weights and growth patterns of indigenous chickens reared intensively in Kenya. Trop Anim Health Prod 42:173-83, 2010. Pubmed reference: 19579054. DOI: 10.1007/s11250-009-9403-y.
Sharifi, A.R., Horst, P., Simianer, H. :
The effect of frizzle gene and dwarf gene on reproductive performance of broiler breeder dams under high and normal ambient temperatures. Poult Sci 89:2356-69, 2010. Pubmed reference: 20952698. DOI: 10.3382/ps.2010-00921.
2003 Missohou, A., Dieng, A., Horst, P., Zarate, VA., Nesseim, T., Tchedre, K. :
Effect of dwarf (dw) and frizzle (F) genes on the performance of layers under Senegalese conditions. Trop Anim Health Prod 35:373-80, 2003. Pubmed reference: 14509543.
2002 Haunshi, S., Sharma, D., Nayal, L.M.S., Singh, D.P., Singh, R.V. :
Effect of naked neck gene (NA) and frizzle gene (F) on immunocompetence in chickens British Poultry Science 43:28-32, 2002. Pubmed reference: 12003334. DOI: 10.1080/00071660120109863.
1999 Yunis, R., Cahaner, A. :
The effects of the naked neck (Na) and frizzle (F) genes on growth and meat yield of broilers and their interactions with ambient temperatures and potential growth rate Poultry Science 78:1347-1352, 1999. Pubmed reference: 10536780.
1997 Kengaku, M., Twombly, V., Tabin, C. :
Expression of wnt and frizzled genes during chick limb bud development Cold Spring Harbor Symposia on Quantitative Biology 62:421-429, 1997. Pubmed reference: 9598377.
1994 Haarenkiso, A.V., Horst, P., Zarate, A.V. :
Direct and Indirect Effects of the Frizzle Gene (F) for the Productive Adaptability of Layers Archiv Fur Geflugelkunde 58:248-257, 1994.
1993 Shoffner, R.N., Otis, J.S., Garwood, V.A. :
Association of dominant marker traits and metric traits in chickens. Poultry Science 72:1405-1410, 1993. Pubmed reference: 8378215.
1992 Bartels, T., Meyer, W., Neurand, K. :
[Skin and plumage changes in domestic birds. II. Plumage changes]. Tierarztl Prax 20:275-81, 1992. Pubmed reference: 1496522.
1990 Bordas, A., Merat, P. :
Growth, Egg Production and Feed Efficiency of Heterozygous Frizzle (Ff+) or Non-Frizzle (F+f+) Chicks and Hens at High Ambient Temperatures Archiv Fur Geflugelkunde 54:66-69, 1990.
Somes, R.G. Jr :
Mutations and major variants of plumage and skin in chickens. In "Poultry Breeding and Genetics" (ed. R.D. Crawford), Elsevier, Amsterdam; Chapter 6 :169-208, 1990.
1963 Lind, L.R. :
Aldrovandi On Chickens. The Ornithology of Ulisse Aldrovandi (1660) volume II, book XIV, translated from the Latin with introd., contents, and notes University of Oklahoma Press, Norman, USA , 1963.
1949 Warren, DC. :
Linkage relations of autosomal factors in the fowl. Genetics 34:333-50, 1949. Pubmed reference: 17247319.
1938 Warren, D.C. :
Mapping the genes of the fowl (abstract) Genetics 23:174 only, 1938. DOI: 10.1093/genetics/23.1.139.
1936 Warren, D.C., Hutt, F.B. :
Linkage relations of Crest, Dominant White and Frizzling in the fowl American Naturalist 70:379-394, 1936. DOI: 10.1086/280676.
1935 Landauer, W., Aberle, S.D. :
Studies on the endocrine glands of frizzle fowl. American Journal of Anatomy 57:99-134, 1935.
1933 Hutt, F.B. :
Genetics of the fowl. II. a four-gene autosomal linkage group. Genetics 18:82-94, 1933. Pubmed reference: 17246679.
1930 Hutt, F.B. :
The genetics of the fowl. I. The inheritance of frizzled plumage Journal of Genetics 22:109-127, 1930.
Landauer, W., Dunn, L.C. :
The “Frizzle” character of fowls - Its expression and inheritance Journal of Heredity 21:291-305, 1930.
1909 Bateson, W. :
Mendel’s Principles of Heredity. Cambridge University Press, London , 1909. URL:
1906 Davenport, C.B. :
"Inheritance in poultry". Washington, D.C.: Carnegie Institution of Washington. Publication 52. :1-136, 1906. DOI: 10.5962/bhl.title.29926.

Edit History

  • Created by Frank Nicholas on 06 Sep 2005
  • Changed by Frank Nicholas on 08 Nov 2012
  • Changed by Frank Nicholas on 26 Nov 2012
  • Changed by Frank Nicholas on 06 Sep 2014
  • Changed by Imke Tammen2 on 22 Dec 2021
  • Changed by Imke Tammen2 on 13 Jan 2022