GM1 (Gangliosidosis) is a recessive genetic disorder effecting multiple body systems in the Portuguese Water Dog. It is an early onset form of lysosomal storage disease, affecting young puppies in the PWD.
Puppies display neurological signs including vision loss, behavioral changes, gait abnormalities and seizures. The lysosomes are a cellular structure that break down and recycle cellular waste. With storage diseases, theses lysosomes malfunction and no longer breakdown and recycle cellular waste resulting in organ malfunction.
There are a variety of gangliosides which are defined by the particular enzyme deficiency that causes the disease. The type seen in the PWD is GM1. It is fatal to affected puppies.
GM1 was first reported in the breed in the 1990’s. Genetic testing for GM1 has been available since September of 1999, making it possible to test parents and no longer produce puppies with this fatal disease. The rate of carriers in the PWD is less than 1%.