Intronic CRISPR Repair in a Preclinical Model of Noonan Syndrome-Associated Cardiomyopathy

Circulation. 2020 Sep 15;142(11):1059-1076. doi: 10.1161/CIRCULATIONAHA.119.044794. Epub 2020 Jul 6.


Background: Noonan syndrome (NS) is a multisystemic developmental disorder characterized by common, clinically variable symptoms, such as typical facial dysmorphisms, short stature, developmental delay, intellectual disability as well as cardiac hypertrophy. The underlying mechanism is a gain-of-function of the RAS-mitogen-activated protein kinase signaling pathway. However, our understanding of the pathophysiological alterations and mechanisms, especially of the associated cardiomyopathy, remains limited and effective therapeutic options are lacking.

Methods: Here, we present a family with two siblings displaying an autosomal recessive form of NS with massive hypertrophic cardiomyopathy as clinically the most prevalent symptom caused by biallelic mutations within the leucine zipper-like transcription regulator 1 (LZTR1). We generated induced pluripotent stem cell-derived cardiomyocytes of the affected siblings and investigated the patient-specific cardiomyocytes on the molecular and functional level.

Results: Patients' induced pluripotent stem cell-derived cardiomyocytes recapitulated the hypertrophic phenotype and uncovered a so-far-not-described causal link between LZTR1 dysfunction, RAS-mitogen-activated protein kinase signaling hyperactivity, hypertrophic gene response and cellular hypertrophy. Calcium channel blockade and MEK inhibition could prevent some of the disease characteristics, providing a molecular underpinning for the clinical use of these drugs in patients with NS, but might not be a sustainable therapeutic option. In a proof-of-concept approach, we explored a clinically translatable intronic CRISPR (clustered regularly interspaced short palindromic repeats) repair and demonstrated a rescue of the hypertrophic phenotype.

Conclusions: Our study revealed the human cardiac pathogenesis in patient-specific induced pluripotent stem cell-derived cardiomyocytes from NS patients carrying biallelic variants in LZTR1 and identified a unique disease-specific proteome signature. In addition, we identified the intronic CRISPR repair as a personalized and in our view clinically translatable therapeutic strategy to treat NS-associated hypertrophic cardiomyopathy.

Keywords: Noonan syndrome; cardiomyopathy, hypertrophic; clustered regularly interspaced short palindromic repeats; gene editing; induced pluripotent stem cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CRISPR-Cas Systems*
  • Cardiomyopathies* / genetics
  • Cardiomyopathies* / metabolism
  • Cardiomyopathies* / therapy
  • Genetic Therapy*
  • Humans
  • Induced Pluripotent Stem Cells / metabolism*
  • Introns
  • Models, Cardiovascular*
  • Mutation*
  • Myocytes, Cardiac / metabolism*
  • Noonan Syndrome* / genetics
  • Noonan Syndrome* / metabolism
  • Noonan Syndrome* / therapy
  • Transcription Factors* / genetics
  • Transcription Factors* / metabolism


  • LZTR1 protein, human
  • Transcription Factors