Novel KLK4 Mutations Cause Hypomaturation Amelogenesis Imperfecta.

Area of Science:

• Genetics
• Biochemistry
• Dentistry

Background:

• Amelogenesis imperfecta (AI) encompasses rare genetic disorders affecting tooth enamel quantity and quality.
• Hypomaturation AI presents with yellow-brown, dull enamel of normal thickness, indicating impaired matrix mineralization.

Purpose of the Study:

• To investigate the genetic causes of hypomaturation AI in four Turkish families.
• To identify novel mutations in genes associated with enamel formation.

Main Methods:

• Whole exome sequencing was performed on affected individuals from four families.
• Mutational analysis focused on identifying genetic variants within the KLK4 gene.
• Functional assays were conducted to assess the impact of identified mutations.

Main Results:

• Two novel homozygous KLK4 gene mutations were discovered: a nonsense mutation (c.170C>A) in families 1-3 and a missense mutation (c.637T>C) in family 4.
• The missense mutation resulted in inefficient translation or an unstable, non-functional KLK4 protein.
• These novel mutations phenotypically resemble previously described KLK4 mutations causing hypomaturation AI.

Conclusions:

• The identified inactivating KLK4 mutations are causative of the hypomaturation AI phenotype.
• This research expands the understanding of KLK4's role in enamel formation and AI pathogenesis.
• Genetic analysis of KLK4 provides insights into the molecular mechanisms underlying defective tooth enamel development.