Clinical and neuropsychological characterization of Jacobsen syndrome (del11q)

Jacobsen Syndrome (JS), also known as 11q Deletion Syndrome (del11q), is a rare genetic disorder affecting approximately 1 in 100,000 births that presents with varied clinical manifestations and severities including intellectual disability, psychomotor delays, and distinctive physical traits. This study offers a detailed analysis of the clinical and cognitive profiles of individuals with JS and examines how these characteristics are related to each other and to genetic variables.

Twenty-nine participants with JS (20 female, mean age 12.48 years, SD = 9.13) underwent standardized assessments assessing cognitive functioning, adaptive behavior, autistic traits, and general psychopathology. A CGH array was used to assess genetic deletions. We employed descriptive and inferential statistical analyses to explore the association between clinical and cognitive characteristics and deletion size.

Sixty percent of participants had verbal language. Mean intelligence quotient was 50.18, the range of adaptive functioning was very broad, and 43% showed behaviors exceeding the ADOS-2 cutoff for autism spectrum classification. A higher cognitive performance was associated with better adaptive skills, including more advanced language skills and with more depressive symptoms or a diagnosis of depression. Larger deletions were associated with more delays in developmental milestones and poorer cognitive functioning. No significant association was found between haploinsufficiency of the KIRREL3 and ARHGAP32 genes and cognitive functioning or autistic characteristics.

Our findings provide deeper insights into the complex relationship between genetic factors and clinical attributes in individuals with JS, revealing notable clinical variability within the JS population. This information may help predict developmental difficulties as genetic findings emerge.