Ventricular arrhythmia and sudden death (MICOS13/QIL1-related) - Rhodesian Ridgeback

What does this test examine?

This genetic test detects the MICOS13 variant c.325G>A in the Rhodesian Ridgeback. The gene has also been known as QIL1. The variant is associated with ventricular arrhythmia, juvenile ventricular arrhythmia, Rhodesian Ridgeback inherited ventricular arrhythmia and sudden cardiac death.

What does this condition mean?

Ventricular arrhythmia means abnormal electrical rhythms arise from the heart ventricles. In susceptible dogs this may lead to abnormal beats, weakness, exercise intolerance, fainting or sudden death. The condition matters because young dogs can appear healthy while still having an abnormal heart rhythm.

MICOS13/QIL1 is involved in mitochondrial structure and energy production. The heart has high energy demands, so disruption of this pathway can be relevant for cardiac rhythm and muscle-cell function.

Inheritance and result

The inheritance is not fully settled. This test is therefore best read as a genetic risk test. A dog with two G alleles does not carry the tested variant. A dog with one A allele carries the risk variant and can pass it on. A dog with two A alleles has the genotype most strongly linked to increased risk in this test.

• GG: the tested risk variant was not detected.
• GA: one copy of the risk variant was detected.
• AA: two copies of the risk variant were detected.

Practical value of this test

This test gives breeders and owners concrete genetic information about a serious heart-risk marker in the Rhodesian Ridgeback. The result helps identify carriers and dogs with two copies, plan matings more carefully and screen relatives within affected lines.

• Helps avoid higher-risk breeding combinations.
• Shows which dogs can pass on the A variant.
• Supports early attention in lines with arrhythmia or sudden death history.
• Adds useful context for purchase, breeding selection and health planning within the breed.