title: Genetic Influence on Accessory Navicular Bone in the Foot: A Korean Twin and Family Study.
abstract: An accessory navicular bone (AN) is the most common accessory ossicle in the foot. The presence of an AN bone can trigger various foot problems, such as posterior tibial tendon pathology, flattening of the medial longitudinal arch, and medial foot pain. Despite the clinical influence of presence of an AN in foot disease, the research regarding its inheritance is still insufficient. A total of 135 pairs of monozygotic (MZ) twins, 25 pairs of dizygotic (DZ) twins, and 676 singletons from families were enrolled in order to estimate genetic influences on AN. After confirmation of zygosity and family relationship with a tandem repeat marker kit and questionnaires, the presence and type of the AN was classified through bilateral feet radiographic examination. The heritability of an AN was estimated using quantitative genetic analysis based on a variance decomposition model considering various types of family relationships: father-offspring pair, mother-offspring pair, and pooled DZ twin and sibling pairs. As a result, approximately 40.96% of the participants in this study had an AN in either foot, with type II being the most common type. The heritability for the presence of any type of an AN in any foot was estimated as 0.88 (95% CI [0.82, 0.94]) after adjusting for age and sex. Specifically, type II AN showed the highest heritability of 0.82 (95% CI [0.71-0.93]). The high heritability of an AN found in this large twin and family study suggests that an AN is determined by the substantial influence of genetic factor.
authors.affiliation: Department of Physical and Rehabilitation Medicine,Samsung Medical Center,Sungkyunkwan University School of Medicine,Seoul,South Korea.
authors.forename: In Yae
authors.initials: IY
authors.lastname: Cheong
authors.affiliation: Department of Physical and Rehabilitation Medicine,Samsung Medical Center,Sungkyunkwan University School of Medicine,Seoul,South Korea.
authors.forename: Hyo Jeong
authors.initials: HJ
authors.lastname: Kang
authors.affiliation: Department of Family Medicine,Samsung Medical Center,Sungkyunkwan University School of Medicine,Seoul,South Korea.
authors.forename: Hyeonyoung
authors.initials: H
authors.lastname: Ko
authors.affiliation: Department of Epidemiology,School of Public Health,Seoul National University,Seoul,South Korea.
authors.forename: Joohon
authors.initials: J
authors.lastname: Sung
authors.affiliation: Department of Family Medicine,Samsung Medical Center,Sungkyunkwan University School of Medicine,Seoul,South Korea.
authors.forename: Yun-Mi
authors.initials: YM
authors.lastname: Song
authors.affiliation: Department of Physical and Rehabilitation Medicine,Samsung Medical Center,Sungkyunkwan University School of Medicine,Seoul,South Korea.
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Hwang
mesh_terms: D000328:Adult; D004200:Diseases in Twins / Q000000981:diagnostic imaging / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D005534:Foot Diseases / Q000000981:diagnostic imaging / Q000235:genetics* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D037081:Posterior Tibial Tendon Dysfunction / Q000000981:diagnostic imaging / Q000235:genetics* / Q000503:physiopathology; D056910:Republic of Korea; D013639:Tarsal Bones / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000503:physiopathology; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics
keywords: accessory navicular bone; foot; heritability; twin