# Right coronary artery originated from left coronary sinus associated with children hypertrophic cardiomyopathy: report of two cases and literature review

## TL;DR

Two children with hypertrophic cardiomyopathy had a rare coronary artery anomaly and unique genetic mutations, showing varied symptoms and disease progression.

## Contribution

Reports two novel pediatric HCM cases with RCA from left coronary sinus and new TTN gene mutation.

## Key findings

- Case 1 is the youngest reported child with HCM and RCA anomaly, showing early cardiac insufficiency.
- TTN gene mutation (p.R16724L) in Case 1 is a novel mutation not previously reported in HCM.
- HCM with anomalous RCA origin may present with diverse symptoms and progress to heart failure.

## Abstract

Coronary artery anomalies are rare both in coronary angiogram and computed tomography angiography. Hypertrophic cardiomyopathy (HCM) is the most frequent inherited cardiac disease. The phenotype of HCM associated with anomalous coronary origin is not commonly seen especially in children.

We describe a case series of two children with HCM combined right coronary artery (RCA) originated from left coronary sinus. Case 1 was a 9-month-old female with TTN gene heterozygous mutation (p.R16724L) who exhibited cardiac insufficiency. Case 2 was a 12-year-old male with MYBPC3 gene heterozygous mutation (p.R820Q) who only exhibited intermittent chest pain. A total of 7 HCM cases with RCA originated from left coronary sinus have been reported with our literature review. Case 1 is the youngest child patient in our report until now. Moreover, the echocardiogram of case 1 is similar with restrictive cardiomyopathy (RCM) and it demonstrates the progression of HCM to heart failure. So, HCM with TTN gene mutation may exhibit cardiac insufficiency more early. And the gene mutation site of TTN has never been reported in previous HCM cases.

HCM coexisted with anomalous origin of RCA has different clinical presentation, and it maybe due to different gene mutation.