Overo - coat pattern

DNA test The DNA test verifies the presence of the mutation associated to the Overo. Frame Overo is a highly desirable...

€35.00

Sample Requirements

30 to 40 - hair roots - envelope or 5 mL - blood - K3 EDTA tube

Send your sample by regular mail or express delivery to:

Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal

Turnaround Time

2 to 5 working days

About the test

This DNA test detects the Frame Overo (O) mutation in the EDNRB gene, responsible for the Frame Overo white coat pattern and associated with Lethal White Foal Syndrome (LWFS).

The test helps identify horses carrying the Overo mutation to support informed breeding decisions and prevent affected foals.

Why test?

Testing is recommended to:

Identify horses carrying the Frame Overo mutation.
Support responsible breeding decisions.
Prevent matings that may produce foals affected by Lethal White Foal Syndrome (LWFS).
Confirm the genetic status of horses with or without the characteristic Overo coat pattern.

How it works

🛒 Purchase the Test: Select and buy the test online.

📧 Receive Instructions: After payment confirmation, receive instructions for sample collection.

✨ Sample Collection: Your veterinarian collects hair roots or a blood sample.

📄 Download Submission Form: Download the printable submission form.

📮 Send Samples: Send your samples by regular mail or express delivery to:

Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal

📄 Receive Results: Get your result certificate by email.

Results

The DNA test verifies the presence of the mutation associated to the Overo and presents results as one of the following:

N/ - Non-Overo horse.
O/N - Frame Overo horse. Horse is heterozygous for the dominant gene causative of frame Overo. A characteristic Overo coat pattern is present in O/N all horses with a copy of frame Overo and will pass this allele to 50% of offspring. Matting two Frame Overo horses has a 50% chance togenerate Lethal White foals and should be avoided.
O/ – A Lethal White Foal Syndrome (LWFS). Homozygous for frame Overo are lethal and newborns survive less than a week old.

Additional information

Frame Overo is a dominant white spotting pattern caused by a mutation in the EDNRB gene.

Horses carrying one copy of the mutation (O/N) typically display the characteristic Frame Overo coat pattern and are healthy. However, breeding two Frame Overo horses together creates a risk of producing foals with Lethal White Foal Syndrome (LWFS).

Foals inheriting two copies of the mutation (O/O) are born almost completely white and suffer from severe intestinal abnormalities caused by the absence of normal nerve development in the digestive tract. Affected foals are unable to survive.

Genetic testing allows breeders to avoid high-risk matings while preserving the desirable Frame Overo coat pattern.