While there are many common variants in DNA known to affect height each has only about a millimeter difference or so. However, a gene variant found in 5% of Peruvians is observed to reduce height by up to 2.2 centimeters. This is the largest observed effect on height by any common gene variation. Rare variations like Marfans syndrome can have much larger effects on height but are found in less than 1% percent of individuals.
The variation is located on the FBN1 gene, a gene which involves producing a protein involved in forming bone, connective tissues, skin and other issues. Marfans syndrome is also linked to a variation within this gene. However the 5% of Peruvians who carry this variant are not considered sick in any pathological definition. Researchers surmised that natural selection favors the variant for shorter individuals, but it is unclear wether there is an evolutionary advantage it gives the those affected currently.