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Musladin-Lueke Syndrome (MLS)

This syndrome was first identified in the early 1990's by Drs. Tony and Judy Musladin and Ada Lueke. This syndrome has been renamed to the Musladin-Lueke Syndrome, in recognition of these dedicated beagle breeders that identified this problem and started investigating it in the beagle population. The genetic research was conducted by  Dr. Mark Neff at University of California at Davis.

A genetic marker test has been developed and this test is available at the very reasonable cost of $50.

A datebase has been established in the UK at

Where you can search to see if dogs have been tested and the results - we are trying to make this an international register - if your dog is tested and the results are not on this list, please email the recording person for more information on what to do.


This syndrome manifests itself by quite specific characteristics. It is often quite easy to identify a puppy/dog affected with this syndrome. Typically, MLS affected beagles have short outer toes and they walk upright on their front feet in what resembles a ballerina stance. Often all four feet are affected. Affected beagles often have tighter skin with limited “scruff”. Their bodies feel hard due to the tight skin, tendons and muscles. They often appear very well muscled. Their head shape is also notably different having a flat skull, higher ear set, ear folds and slanted eyes. Tails are often carried in a straight, stiff fashion and some beagles have noticeable kinks in the tail as well. The syndrome can be determined very early on at about 2 to 4 weeks if you know what to look for.
Here is a picture of  an entire litter at approximately 4 weeks of age.   There is little or no difference at a quick glance.  The MLS pups are the second one in the top row and the first and third in the bottom row.  Note--the MLS pups have their tails stuck straight up in the air.  You can also see the stiff legs starting to really show in the back legs, but front legs are still normal looking.  You can't see the high toes in the front, but they are easy to see in the back legs.

The syndrome progressively gets worse until about 1 year of age when the dog then stabilizes. It is also important to note that there are varying degrees of “affectedness” with many beagles and breeders should look at any or all of the above indicators to assist in determining an MLS diagnosis or a potential MLS carrier. Ear folds, high toes or tight skin as a single trait does not automatically indicate carrier or affected status. There have been dogs with ear folds, high toes or tight skin that were not carriers. Dogs with total normal appearance have been determined to be carriers. The only way to determine normal or carrier status is to TEST. Unless there are associated congenital or genetic problems, these beagles will have a normal life span. A genetic marker test has been developed and this test is available through the Veterinary Genetics Laboratory (VGL) of the School of Veterinary Medicine at the University of California, Davis. The DNA test is being offered at the very reasonable cost of $50.

MLS is inherited as a recessive trait. Current evidence suggests that dogs that have two copies of the mutant gene are affected with MLS, though the severity of clinical signs can be variable. Dogs inheriting only one copy of the mutant gene can show subtle signs but do not appear to have health-related defects. To the best available knowledge, carriers cannot be identified based on their appearance. This test determines whether dogs are normal (clear of the mutation), carrier (have one mutant copy), and affected (have two mutant copies).

N/N: Normal. The dog does not have the MLS gene.
N/MLS: Carrier. The dog carries one copy of the MLS gene.
MLS/MLS: Affected. The dog has two copies of the MLS gene.

If a carrier dog (with a single mutant copy of the gene) is used in a mating, an offspring from the cross has a 50% chance of inheriting the mutation from this parent. If two carriers are mated, 25% of the offspring in the litter are expected to have MLS and another 50% of the puppies are expected to be carriers. Mating two clear dogs will only produce clear puppies, which need not be tested by DNA.


The links below will provide more information, pictures and comments from owners of beagles affected with MLS.

Chinese Beagle Syndrome Revisited-An Article in the March 2005 Show Beagle Quarterly
A Case Study-Printed in the SBQ March 2005        
Pictures of Case Study Beagle
Excerpts from Owners of beagles with CBS
Recently Published (2010) article

Most owners and breeders that have MLS beagles have noted an abnormal ear cartilage. It may be felt as early as 3 weeks of age. Some beagles just have a odd "ribbon" type feel in the ear and others actual have extra folds from the cartilage. Abnormal ear carriage can be seen almost at birth.

Ears that stuck out at an odd angle at birth was noted in two litters. The ear stands out and does not fold down beside head as a normal puppy would. At two to three weeks of age they fell into a more natural position. In all cases, (with one exception) these puppies were carriers or affected.

Slightly older dogs