Mutations in DYNC2LI1 disrupt cilia function and cause short rib polydactyly syndrome

Area of Science:

• Genetics and Developmental Biology
• Skeletal Dysplasias
• Ciliary Biology

Background:

• Short rib polydactyly syndromes (SRPSs) are severe, lethal skeletal disorders.
• Mutations in genes involved in intraflagellar transport (IFT) are known causes of SRPS.
• However, genetic causes for all SRPS cases remain unidentified.

Purpose of the Study:

• Identify novel genetic causes of SRPS.
• Elucidate the functional role of a newly identified gene in SRPS pathogenesis.
• Further understand the mechanisms of intraflagellar transport (IFT) and ciliogenesis.

Main Methods:

• Whole-exome sequencing in affected families.
• Analysis of primary fibroblasts to assess protein function.
• Investigation of ciliary structure and function, including Hedgehog pathway signaling.

Main Results:

• Identified mutations in cytoplasmic dynein-2 light intermediate chain 1 (DYNC2LI1) as a cause of SRPS in three families.
• Demonstrated that DYNC2LI1 is crucial for dynein-2 complex stability.
• Observed abnormal cilia length, Hedgehog pathway impairment, and IFT accumulations in cells with DYNC2LI1 mutations.

Conclusions:

• DYNC2LI1 is a newly identified SRPS gene, expanding the known genetic heterogeneity of these disorders.
• DYNC2LI1 mutations disrupt dynein-2 complex stability, leading to ciliopathy phenotypes.
• This study highlights the critical role of DYNC2LI1 in ciliary function, Hedgehog signaling, and skeletal development.