Dr. Lance Perryman, who contributed to the discovery that Severe Combined Immunodeficiency (SCID) is inherited as an autosomal recessive condition in Arabian horses, recently took the time to share some insight with curiousYOUNGwriters (cYw).
As was stated in our feature piece on SCID, “Arabian horses aren’t being utilized for research purposes as often as their benefits suggest,” and Dr. Perryman could offer some reasons as to why this is the case.
The Arabian horse was first described as a model for SCID in 1973, and for about the next decade it was the only available animal model for this disorder in children. The initial research focused on treatment. Researchers asked and answered questions such as, “Can treatments be developed in horses that might be applicable to children?” and, “What is the precise gene defect in the Arabian horse and is it possible to test them to determine if they carry the gene defect?”
But researchers have since moved away from this model mainly because the gene defect that causes SCID in the Arabian horse is rarely the same gene defect that causes SCID in children. Therefore, from a molecular standpoint, it’s probably not the best model for the condition in children.
Also, since the gene defect that causes SCID has been very clearly defined, the need in the Arabian horse industry has been fulfilled; namely, anybody who’s planning on breeding or purchasing an Arabian horse now has the ability to have the horse tested to ensure that it doesn’t carry the defective gene. For these reasons, it’s unlikely that the Arabian horse model will be used extensively for SCID research in the future.
But if the Arabian horse isn’t the desired model for SCID, then what is? The answer lies in another uncommon animal model: “I’m going to speculate that, today, the Basset Hound model might be the best animal model for studying the disorder in children,” says Perryman. The main reason is that the Hounds have the gene defect that’s most commonly involved with SCID in children. Simply put, the defect matches up, and this is important when considering potential animal models.
Besides the fact that Hounds are genetically similar to children in terms of the gene that expresses SCID, they also cost less to feed, have shorter gestation periods, and produce more offspring per year than Arabian horses (see chart below). Mice are also a viable model for SCID research in children.
Having been through the research process many times himself, Dr. Perryman finished with this piece of advice for young researchers: “I think that the key to success and happiness in research is to have an inquisitive mind.”
In other words, stay curious.