Genomic Sequencing in Patients With HCM Undergoing Septal Myectomy

The hypothesis is that sporadic or simplex occurrences of what are typically autosomal
dominantly inherited diseases can instead be caused my mosaic mutations, specifically,
mutations in the heart itself.

This hypothesis mandates that investigators sequence both affected and unaffected tissues,
which in this case, investigators will construe to be peripheral blood DNA and discarded
myocardium from cardiac procedures.

Eligible individuals will first undergo informed consent to be part of the study prior to
their scheduled myomectomy. The study participants will also have phlebotomy for research
samples.

The NIH Intramural Sequencing Center (NISC) will perform paired exome or genome sequencing
and we will first screen for germline mutations in known cardiomyopathy genes that meet ACMG
standards of likely pathogenic or pathogenic.

Then, if this is negative, investigators will screen for sequence variants that are present
in cardiac tissue but absent in the blood DNA. Investigators will also screen blood DNA for
secondary findings in genes recommended for annotation and results return by the ACMG and
sequence variants deemed clinically relevant in this gene set will be validated in a
CLIA-certified laboratory and the results returned to that participant.

Inclusion Criteria:

- Patient is 18 years and older has a clinical diagnosis of hypertrophic cardiomyopathy.

- Patient scheduled for clinically-indicated myomectomy.

- Patient has a negative family history of hypertrophic cardiomyopathy

- Patient is willing to receive results of secondary variant screen

Exclusion Criteria:

- Pregnant

- Inability to give informed consent