Left-Sided Heart Defects and Laterality Disturbance in Hypoplastic Left Heart Syndrome

Hisato Yagi1, Cecilia W Lo1

  • 1Department of Developmental Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15201, USA.

Insights

Hypoplastic left heart syndrome (HLHS) involves left-sided heart defects, potentially caused by laterality disturbance. This disturbance affects left-right patterning genes, impacting cardiovascular development and blood oxygenation.

Area of Science:

  • Developmental Biology
  • Genetics
  • Cardiovascular Science

Background:

  • Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect.
  • The cause of left-sided heart hypoplasia in HLHS is not fully understood.
  • Co-occurrence of HLHS with situs defects suggests a potential laterality disturbance.

Purpose of the Study:

  • Investigate the role of laterality disturbance in HLHS.
  • Explore the genetic basis of left-right patterning defects in HLHS.
  • Understand the integration of heart development with asymmetric patterning.

Main Methods:

  • Analysis of HLHS patient genetic variants in left-right patterning genes.
  • Examination of HLHS mutant mouse models (Ohia mice).
  • Investigation of gene regulation by Sap130 within the Sin3A chromatin complex.

Main Results:

  • Pathogenic variants in left-right patterning genes are found in HLHS patients.
  • Ohia mice with HLHS exhibit splenic defects, indicative of heterotaxy.
  • Sap130 mutations in Ohia mice affect Lefty1 and Snai1, crucial for left-right patterning.

Conclusions:

  • Laterality disturbance is implicated as a mediator of left-sided heart defects in HLHS.
  • Shared mechanisms between HLHS and other congenital heart defects (CHD) may involve laterality.
  • Integration of cardiac development with left-right patterning is vital for cardiovascular asymmetry and efficient oxygenation.

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