Presence, Severity, and Functional Associations of Incomplete Hippocampal Inversion in 22q11.2 Deletion Syndrome

Area of Science:

• Neuroimaging
• Developmental Neuroscience
• Genetics

Background:

• The hippocampus is smaller and functionally disrupted in 22q11DS.
• Incomplete hippocampal inversion (IHI) is a developmental abnormality that may contribute to these hippocampal differences.
• The prevalence and impact of IHI in 22q11DS are largely unknown.

Purpose of the Study:

• To investigate the prevalence and severity of IHI in individuals with 22q11DS compared to healthy controls.
• To examine the association between IHI and hippocampal morphology.
• To explore the functional consequences of IHI on memory and psychopathology in 22q11DS.

Main Methods:

• Structural MRI data from 108 individuals with 22q11DS and 633 healthy controls were analyzed.
• Presence and severity of IHI were assessed bilaterally.
• Hippocampal volume, memory performance, and psychopathology were evaluated.

Main Results:

• IHI was significantly more prevalent and severe in individuals with 22q11DS compared to controls in both hemispheres.
• IHI was associated with altered hippocampal subregional volumes, particularly the head and tail.
• Left IHI was linked to poorer face memory performance in the 22q11DS group.

Conclusions:

• High prevalence of IHI in 22q11DS indicates significant hippocampal morphological alterations.
• IHI is associated with memory deficits in 22q11DS.
• Further longitudinal studies are needed to understand the role of IHI in 22q11DS.