Two mutations in IFITM5 causing distinct forms of osteogenesis imperfecta

Area of Science:

• Genetics
• Molecular Biology
• Orthopedics

Background:

• Osteogenesis Imperfecta (OI) type V is linked to mutations in the IFITM5 gene.
• Previously, only a single heterozygous mutation (c.-14C>T) was identified in all reported patients.
• This mutation causes characteristic symptoms like hyperplastic callus and forearm interosseous membrane calcification.

Observation:

• This study reports two new cases of IFITM5 mutations.
• One patient presented a de novo c.119C>T mutation (p.Ser40Leu) with prenatal limb shortening, lacking typical OI type V signs.
• Another patient had a de novo c.-14C>T mutation, exhibiting classic OI type V features.

Findings:

• The findings demonstrate allelic heterogeneity in IFITM5 mutations.
• A novel mutation (c.119C>T) resulted in a different clinical presentation than the previously known mutation.
• The recurrent mutation (c.-14C>T) was also observed as a de novo event.

Implications:

• This expands the understanding of the genetic basis of Osteogenesis Imperfecta type V.
• It suggests that IFITM5 mutations may present with a broader spectrum of clinical phenotypes.
• Further research is needed to explore the full range of IFITM5 mutations and their associated clinical manifestations.