Inclusion Criteria:

• Males or females with a confirmed diagnosis of childhood onset (<16 years) PCM
• Males or females with childhood onset (<16 years) of a rare inherited cardiac condition likely to be a monogenic condition
• Capacity for parents to provide informed consent
• Genotype negative following local standard diagnostic ICC gene panel
• Family members of patients with ICC, both affected and unaffected

Exclusion Criteria:

• Parents who lack capacity to provide consent on behalf of their children/themselves
• Onset over 16 years
• Significant teratogen exposure (including maternal diabetes) likely to contribute to cardiac dysfunction (following discussion with Cardiologist)
• Significant coronary heart disease likely to contribute to cardiac dysfunction (following discussion with Cardiologist)
• Other secondary causes of cardiac dysfunction likely to explain the phenotype of the patient
• Patients with a confirmed genetic diagnosis (patients with variants of uncertain significance are not excluded).