In this work, we report on a patient with a homozygous FBN3 missense variant identified by a combined SNP-array and whole-exome sequencing approach and a phenotype characterized by cognitive impairment, developmental delay, learning difficulties, strabismus, arched palate, dental and genital anomalies, brachydactyly/syndactyly, and obesity, supporting that FBN3 alteration could be associated with a phenotype resembling BBS. This evidence concerns the gene FBN3 and Cognitive impairment.