Polymorphisms in human muscarinic receptor subtype genes

Area of Science:

• Pharmacogenomics
• Molecular Biology
• Genetics

Background:

• Polymorphisms are common in muscarinic receptor genes (M₁, M₂, M₃).
• Existing genotype-phenotype associations are primarily for brain functions, with limited data for cardiac and airway functions.

Purpose of the Study:

• To review the current state of knowledge on muscarinic receptor gene polymorphisms.
• To identify gaps in understanding genotype-phenotype relationships and their clinical implications.

Main Methods:

• Literature review of studies on muscarinic receptor subtype gene polymorphisms.
• Analysis of reported genotype-phenotype associations across various physiological systems.
• Assessment of mechanistic and drug response studies.

Main Results:

• No robust genotype-phenotype associations have been established for any phenotype.
• The causative role of specific polymorphisms versus linkage disequilibrium remains unclear.
• Most data are from cross-sectional studies, lacking mechanistic and drug response investigations.

Conclusions:

• The field of muscarinic receptor genomics is nascent.
• Further research is essential to elucidate the role of muscarinic receptor gene variability in physiology, pathophysiology, and pharmacotherapy.