BMP4 mutations in tooth agenesis and low bone mass

Area of Science:

• Genetics
• Molecular Biology
• Dental Medicine

Background:

• Tooth agenesis (TA) is a common developmental anomaly with diverse genetic causes.
• Bone morphogenetic protein 4 (BMP4) plays a crucial role in embryonic development, including tooth formation.

Purpose of the Study:

• To investigate the genetic basis of isolated tooth agenesis (TA) by identifying novel causative genes.
• To explore the association between BMP4 gene mutations and TA, as well as related skeletal phenotypes.

Main Methods:

• Whole exome sequencing (WES) and Sanger sequencing were employed to analyze BMP4 in 120 TA patients.
• Dual-energy X-ray absorptiometry (DEXA) was used to assess bone mineral density.
• In vitro functional assays were performed on BMP4 mutants.

Main Results:

• Four mutations in the BMP4 gene, including three novel missense mutations, were identified in 120 TA probands.
• BMP4 mutations were associated with autosomal dominant inheritance of various dental anomalies.
• Patients with BMP4 mutations exhibited early-onset osteopenia or osteoporosis and reduced Smad signaling activation.

Conclusions:

• Mutations in the BMP4 gene are an uncommon cause of tooth agenesis (TA) in humans.
• This study highlights BMP4 mutations as a potential cause of human skeletal diseases, including TA and bone density disorders.