Behavioural phenotype of a patient with a de novo 1.2 Mb chromosome 4q25 microdeletion

A female patient, 20 years of age, is reported with a history characterized by developmental and psychomotor delay, and during grammar-school period increasing learning problems, ritualistic behaviours and social withdrawal. Subsequently, challenging and autistic-like behaviours became prominent. The patient showed mild facial dysmorphisms, long thin fingers with bilateral mild short V metacarpals, and hyperlaxity of the joints. Neuropsychiatric examination disclosed obsessive, ritualistic behaviours and vague ideas of reference. Neuropsychological assessment demonstrated mild intellectual disability, mental inflexibility and incongruent affect. MRI-scanning of the brain showed no relevant abnormalities. Genome wide SNP array analysis revealed a 1.2 Mb de novo interstitial microdeletion in 4q25 comprising 11 genes, that was considered to be causative for the developmental delay, perseverative cognitive phenotype and dysmorphisms. To the authors knowledge, this is the first report of a de novo 4q25 microdeletion that presents with a specific behavioural phenotype.