Importantly, the heterozygous loss of RBFOX2 function results from de novo frameshift, nonsense, or splice site mutations, and the reduced expression of RBFOX2 due to copy number loss is significantly enriched in patients with hypoplastic left heart syndrome (HLHS) displaying the left ventricle obstruction phenotype [80,81,82,83]. The gene discussed is RBFOX2; the disease is hypoplastic left heart syndrome.