Identifying a failure-to-thrive fraternal twin profile with 3q29 deletion syndrome

In 2005, the 3q29 deletion syndrome was identified and defined as a rare chromosomal anomaly that effects approximately one in 30,000-40,000 children. It has a complex neuropsychiatric profile, often resulting in developmental delays, intellectual disabilities, attentional deficits, classic physical traits, and behavioral health disturbances, including social and emotional issues. Rarely has this syndrome been seen and evaluated in fraternal twins, only one of whom has the 3q29 deletion syndrome. This case study highlights Twin 1's strengths and weaknesses and compares her 2020 neuropsychological data, including a comparison of her Reitan-Indiana Neuropsychological Battery (RINB) results to her 2022 profile, which reveals a failure-to-thrive profile.