title: Use of robust statistical methods to determine the effect of fragile X on means and variance components of a quantitative trait.
abstract: Owing to the presence of outliers, an estimated 3.5% in the ridge breadth data and 1.7% in the height data, the effect of fragile X on height and ridge breadth was examined using robust statistical techniques for data collected from 54 families afflicted with this disorder. It is shown that fragile X affects ridge breadth and height in a different manner. Fragile X women had a greater mean ridge breadth than normal women, whereas there was a similar trend, but no significant difference, between normal and fragile X men. Fragile X men were shorter than normal men, but no significant difference between the mean height of normal and fragile X women was observed. However, fragile X girls were shown to grow more quickly and to stop growing earlier than normal girls. An examination of the covariance between relatives classified according to fragile X status showed that for both traits the effect of fragile X was to reduce the covariance between parents and offspring, which produced the effect of departure from an additive polygenic model of inheritance.
authors.affiliation: Department of Statistics, La Trobe University, Bundoora, Australia.
authors.forename: R M
authors.initials: RM
authors.lastname: Huggins
authors.forename: D Z
authors.initials: DZ
authors.lastname: Loesch
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D003878:Dermatoglyphics; D005260:Female; D005600:Fragile X Syndrome / Q000453:epidemiology* / Q000235:genetics; D006225:Hand; D006801:Humans; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D015233:Models, Statistical; D016011:Normal Distribution; D010375:Pedigree; D010641:Phenotype; D012044:Regression Analysis; D012737:Sex Factors