Response to Lefebvre et al.

Area of Science:

• Genetics
• Developmental Biology
• Orthopedics

Background:

• Congenital scoliosis (CS) is a common vertebral malformation affecting up to 1 in 1000 births.
• TBX6 was recently identified as the first disease gene associated with CS, with mutations found in approximately 10% of patients.
• Spondylocostal dysostosis (SCD) is a rare skeletal dysplasia impacting the spine and ribs, also potentially linked to TBX6 mutations.

Discussion:

• This study investigated the pathogenicity of three missense variants in TBX6 reported in two SCD patients.
• Luciferase assays yielded negative results, contradicting the proposed pathogenicity of these variants in SCD.
• The findings suggest that the two SCD patients are more likely compound heterozygotes for null TBX6 mutations and a common risk haplotype, similar to CS patients.

Key Insights:

• The pathogenicity of specific TBX6 missense variants in spondylocostal dysostosis (SCD) is questioned.
• Congenital scoliosis (CS) and SCD may share similar genetic mechanisms involving TBX6.
• The role of compound heterozygosity with null mutations and common risk haplotypes in TBX6-related disorders is highlighted.

Outlook:

• Further research is needed to elucidate the precise role of TBX6 variants in skeletal dysplasias.
• Investigating the genetic architecture of CS and SCD may reveal overlapping etiologies.
• Understanding TBX6's function in vertebral development is crucial for diagnosing and potentially treating these conditions.