Fetal-onset neuroaxonal dystrophy / FNAD (MFN2-related) - Beagle and Giant Schnauzer

What does this test analyse?

This genetic test analyses the MFN2 c.1617_1619delGGA variant for neuroaxonal dystrophy, also known as NAD / fetal-onset neuroaxonal dystrophy (FNAD), in Beagles and Giant Schnauzers.

Neuroaxonal dystrophy is an inherited neurological disorder in which nerve pathways in the brain, spinal cord or peripheral nervous system become damaged. As a result, communication between nerve cells and muscles becomes progressively disrupted.

What does this condition mean?

This MFN2-related form is a very severe, lethal NAD form. Affected puppies can be born with stiff joints, scoliosis, arthrogryposis, underdeveloped nervous system structures and respiratory failure at or shortly after birth.

Typical signs can include loss of coordination, ataxia, tremor, weakness, abnormal posture, toe dragging, behavioural changes, vision problems or a rapidly progressive neurological presentation. Some NAD forms start in very young puppies; other variants become visible later in life.

Inheritance and result

The trait is inherited as an autosomal recessive condition. Clear dogs have two normal copies. Carriers have one copy of the tested variant and can pass it on. Dogs with two copies have the genotype that causes this form of NAD.

Practical value of this test

• The test helps breeders identify carriers before two carriers are combined.
• The result enables targeted breeding plans without automatically losing healthy carriers from valuable lines.
• For owners, the test gives clarity about genetic risk in a breed or line where NAD occurs.
• In young dogs with neurological signs, the result can support genetic interpretation.
• Variant status can be documented reliably in pedigrees, breeding advice and long-term selection.
• For severe or early-onset NAD forms, testing helps avoid unexpected affected puppies in future combinations.

For this lethal form, carrier detection before breeding combinations is crucial to prevent affected puppies.