PDE3A mutations cause autosomal dominant hypertension with brachydactyly

Area of Science:

• Genetics
• Cardiovascular Medicine
• Endocrinology

Background:

• Cardiovascular disease, particularly hypertension, is a leading global cause of mortality.
• Understanding the genetic underpinnings of hypertension, such as Mendelian hypertension, is crucial for elucidating blood pressure regulation mechanisms.
• Brachydactyly type E (BDE) is a rare skeletal disorder with variable clinical manifestations.

Purpose of the Study:

• To identify the genetic cause of a rare syndrome combining Mendelian hypertension and brachydactyly type E (HTNB).
• To investigate the molecular mechanisms by which mutations in PDE3A lead to the observed phenotype.
• To explore the potential of PDE3A as a therapeutic target for hypertension.

Main Methods:

• Genetic analysis of six unrelated families with HTNB to identify causative mutations.
• In vitro studies using mesenchymal stem cell-derived vascular smooth muscle cells (VSMCs) and chondrocytes to analyze mutant PDE3A function.
• Assessment of cellular signaling pathways, including cAMP hydrolysis, cell proliferation, and levels of phosphorylated VASP and PTHrP.

Main Results:

• Six distinct missense mutations in the PDE3A gene were identified in families with HTNB.
• Mutations resulted in a gain of function for phosphodiesterase 3A (PDE3A), characterized by increased cAMP-hydrolytic activity and enhanced cell proliferation.
• Dysregulated levels of phosphorylated VASP and PTHrP were observed, suggesting altered cellular signaling pathways.

Conclusions:

• Mutations in PDE3A are the cause of the described Mendelian hypertension and brachydactyly syndrome (HTNB).
• The gain-of-function mutations in PDE3A lead to severe, salt-independent hypertension, increased fibroblast growth, and other associated features.
• PDE3A, particularly in VSMCs, represents a promising therapeutic target for managing hypertension.