Porcine Stress Syndrome / PSS (RYR1-related) - Pig

What does this test examine?

This DNA test examines the RYR1 c.1843C>T variant in pigs. This variant is known for Porcine Stress Syndrome, also called PSS, malignant hyperthermia, MH, halothane sensitivity or the former HAL gene. RYR1 encodes a calcium channel in skeletal muscle. When both copies of the tested variant are present, calcium regulation in muscle cells is disturbed and the animal can react extremely strongly to stress triggers.

What does PSS mean in practice?

PSS matters for health, animal welfare and pork quality. Affected pigs can develop a rapid rise in body temperature, muscle rigidity, acidosis, breathing problems and sudden death after transport, heat, handling, mating, anaesthesia or other stress. After slaughter, the same sensitivity can contribute to rapid muscle changes and abnormal meat quality, including pale, soft and exudative pork.

The test is therefore useful for breeding, herd management and selection. A carrier usually looks normal, but can pass the variant to offspring. Genotyping makes it possible to identify carriers, avoid carrier x carrier matings, monitor risk lines and reduce the chance of producing stress-susceptible piglets.

Practical value of this test

• Breeding selection: distinguishes clear animals from carriers reliably.
• Risk management: prevents carrier x carrier combinations that can produce piglets with two variant copies.
• Animal welfare: supports selection against stress sensitivity and acute reactions during handling or transport.
• Meat quality: helps manage lines where PSS or PSE sensitivity is unwanted.

Inheritance and result

Porcine Stress Syndrome caused by this variant is autosomal recessive. An animal with C/C does not carry the tested variant. An animal with C/T is a carrier and can pass the variant on. An animal with T/T has two copies of the variant; this genotype causes PSS/halothane sensitivity and is genetically unsuitable for combinations where stress-susceptible offspring must be avoided.