Joining the fingers: a HOXD13 Story

Area of Science:

• Developmental Biology
• Genetics
• Clinical Medicine

Background:

• Synpolydactyly (SPD) is a rare congenital limb malformation.
• SPD is characterized by fused digits and extra digits in a syndactylous web.
• Most SPD cases are associated with mutations in the HOXD13 gene.

Purpose of the Study:

• To explore the genotype-phenotype correlations in Synpolydactyly.
• To understand the role of HOXD13 mutations in limb development.
• To investigate the pathogenic mechanisms of SPD.

Main Methods:

• Analysis of HOXD13 gene mutations in SPD patients.
• Review of clinical heterogeneity and reduced penetrance of SPD.
• Utilizing mouse and chick animal models for in vivo studies.

Main Results:

• HOXD13 mutations, including those outside known domains, cause diverse SPD features.
• Mutations in the N-terminal polyalanine tract or C-terminal homeodomain lead to typical or atypical SPD.
• Clinical presentation of SPD shows heterogeneity and reduced penetrance, complicating diagnosis.

Conclusions:

• HOXD13 mutations are key to SPD pathogenesis.
• Animal models are essential for studying HOXD13 function and SPD mechanisms.
• Further research is needed to fully elucidate genotype-phenotype correlations in SPD.