Variants in DOCK3 cause developmental delay and hypotonia.

Area of Science:

• Genetics and Molecular Biology
• Neuroscience
• Developmental Biology

Background:

• The DOCK3 gene encodes the Dedicator of cytokinesis 3 (DOCK3) protein, a guanine nucleotide exchange factor primarily expressed in the brain and spinal cord.
• DOCK3 plays a crucial role in cellular signaling pathways, particularly those involving actin cytoskeleton regulation and cell migration.

Observation:

• Whole exome sequencing (WES) was used to identify genetic variants in three unrelated individuals with developmental delay and hypotonia.
• The study identified truncating, splice site, and missense variants in the DOCK3 gene across the affected individuals.
• In vitro assays demonstrated reduced Rac1 activation in cells with DOCK3 missense variants, suggesting a loss-of-function mechanism.

Findings:

• Three novel cases of DOCK3-related neurodevelopmental syndrome are reported, characterized by developmental delay, hypotonia, and gait abnormalities.
• The identified variants, including missense mutations within or near the DHR-2 domain, support a loss-of-function mechanism for DOCK3 in neurodevelopment.
• The findings expand the genotypic and phenotypic spectrum of DOCK3-related disorders.

Implications:

• This research reinforces the critical role of DOCK3 in normal neurodevelopment and highlights its significance in a spectrum of neurological disorders.
• Understanding DOCK3's function and the impact of its variants can inform diagnostic approaches and potential therapeutic strategies for related neurodevelopmental conditions.
• Further investigation into the variable phenotypes associated with missense variants is warranted to fully elucidate DOCK3's role.