Validation of Hagerman’s behavioral phenotype for fragile X syndrome among men with intellectual disability

Purpose: The behavioral phenotype of fragile X syndrome (FXS) and intellectual disability (ID) proposed by Hagerman et al. (2009) was primarily based on data from male children and teens. The purpose of this study was to promote a better understanding of how this condition manifests in adults. Design/methodology/approach: A total of 18 men of FXS were paired with men with Down syndrome on the basis of age and level of ID. A screening checklist was created on the basis of existing scales and the Hagerman et al. (2009) behavioral phenotype and completed by care providers. Findings: Five of the 12 features of the phenotype were significantly more present among men with FXS than in men with Down syndrome. Originality/value: This study provides partial confirmation for Hagerman et al.’s (2009) behavioral phenotype of FXS among men with moderate ID and identified some traits that warrant further investigation.