Standard  and health

Like every breed, the Belgian Shepherd faces various types of genetic diseases, which, however, can be tested. And because in our kennel we pay attention to the health of our breeding and breed, we tested our breeding bitches and select only tested stud dogs. 

Breed standard : https://www.fci.be/Nomenclature/Standards/015g01-en.pdf

CJM - Cardiomyopathy and juvenile mortality in Belgian Shepherds

Cardiomyopathy with juvenile mortality (CJM) is an inherited disease characterized by early death of puppies at birth or at a maximum age of six to eight weeks. The puppies initially develop normally, but then they show unspecific clinical signs like vomiting, uncoordinated movements (trembling, stumbling) and respiratory problems (dyspnea). The puppies die several days after onset of the first clinical signs, usually due to heart failure.

This mutation is caused by mutation c. 1054G>A in YARS2 gene that encodes mitochondrial tyrosyl-tRNA synthetase 2. Eukaryotic organisms have two tyrosyl-tRNA synthetases - cytoplasmic (YARS1) and mitochondrial (YARS2). These two types of synthetases have evolutionarily conserved sequence motifs (we can find them in animals, fungi, and even in plants) which points to the importance of conservation of correct sequence for the function of an organism. The mutation c. 1054G>A affects the function of YARS2 gene and hampers the correct recognition and binding of the mitochondrial tRNA. The loss of YARS2 function can also be observed in human patients who have similar symptoms as Belgian Shepherds and suffer from myopathy, lactic acidosis, anaemia and results in early death.

The mutation that causes the CJM is inherited autosomal recessively. The disease develops only in individuals that inherited the mutated gene from both parents. These individuals are designated as P/P (positive/positive). The carriers of the mutated gene referred to as N/P (negative/positive) have only one mutated gene from one parent and show no clinical symptoms. However, they pass on this disease to their offspring. Genetic testing can detect the presence of the mutated allele and prevent further spreading of this disease.

SDCA 1 - Spongy cerebellar degeneration with cerebellar ataxia 

Spongy cerebellar degeneration with cerebellar ataxia (SDCA1) is a neurodegenerative disease that affects dogs of Belgian shepherd breed. The disease is caused by point mutation c.986T>C in KCNJ10 gene. This gene encodes potassium channels (K+ channels) that are present in central nervous system, eyes, internal ear and kidneys. Function of K+ channel in cerebellar cortex altered due to this mutation results in extracellular accumulation of potassium, reduction of membrane potential and subsequent occurrence of neurological attacks. The mutation was found in the Belgian Shepherds Malinois and Tervueren. In other varieties of Belgian Shepherd, this mutation has not been found so far. However detection of such mutation in future is not excluded. The estimated frequency of mutant allele in the Malinois population is 2.9%. The occurrence of this mutation in breeds that were cross-bred with Belgian shepherds in the past, for example in some lineages of Dutch shepherds, cannot be excluded.

The first signs appear before the age of two months. It is reported that the signs can be usually observed between 4.5 and 8.5 weeks of age. The affected dogs show a characteristic gait with hind limbs held wide apart to maintain the stability and improve the coordination of leg movement. There can be observed further signs such as stumbling, tremor, loss of stability, jumping about, staggering and falling. In some dogs, muscular spasm may occur triggered by stress situations or exercise activities. The prognosis usually leads to euthanizing of the affected dog.

SDCA1 is a recessively inherited disease. The disease develops in dogs which inherit the mutated gene from each parent. These dogs are designated as P/P (positive/positive). The carriers of the mutated gene are designated as N/P (negative/positive). The carriers inherited the mutated gene from one parent only and are without clinical signs. However, they pass the disease on to their offspring. When mating two heterozygotes (N/P), there will be theoretically 25% of the offspring healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will be affected by SDCA1. Mating one healthy dog (N/N) with a carrier of this mutation (N/P) will theoretically produce 50% carriers and 50% healthy offspring. If a carrier (N/P) is mated with an affected dog (P/P), there will be theoretically 50% affected dogs and 50% carriers.

SDCA 2 - Spongy cerebellar degeneration with cerebellar ataxia 

The SDCA2 is a subtype of a neurodegenerative disease known as spongy degeneration with cerebellar ataxia that affects Malinois dogs and other varieties of the Belgian shepherd breed.

SDCA2 is relatively variable as to disease onset, severity and histopathological lesions. The cerebellar dysfunction occurs at the age of 4 to 6 weeks. The main symptoms are ataxic gait, balance loss and insufficient movement coordination (stumbling, staggering, falling and intention tremor). All affected puppies show wide-based ataxic gait, which is more obvious in the hind limbs. In this way the puppies try to keep stability and improve the movement coordination. The prognosis is poor and usually ends by euthanizing the dog.

SDCA2 is a recessively inherited disease. The disease develops in dogs which inherit the mutated gene from each parent. These dogs are designated as P/P (positive/positive). The carriers of the mutated gene are designated as N/P (negative/positive). The carriers inherited the mutated gene from one parent only and are without clinical signs. However, they pass the disease on to their offspring. When mating two heterozygotes (N/P), there will be theoretically 25% of the offspring healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will be affected by SDCA2. Mating one healthy dog (N/N) with a carrier of this mutation (N/P) will theoretically produce 50% carriers and 50% healthy offspring. If a carrier (N/P) is mated with an affected dog (P/P), there will be theoretically 50% affected dogs and 50% carriers.

D Locus (Dilution locus), allele d1

The allele with this mutation is designated as d1-allele.

The inheritance of the diluted colour is autosomal recessive that means that the phenotype of diluted colour is expressed in case of genotype d1/d1. In dogs with black coat, the black turns into grey (blue) and the red colour turns into cream colour.

Degenerative Myelopathy

Degenerative myelopathy (DM) is a progressive neurodegenerative disease which occurs in wide range of dogs approximately at eight years of age. Affected dogs develop non-painful weakness of the pelvic limbs that causes problems with coordination and unsteady gait, than the signs slowly progress to muscle atrophy, ataxia, incontinence and ends with paralysis of hind limbs. The symptoms accompanying this disease are so severe that the dog dies within 3 to 5 years after occurrence of the first signs. However, the dog is euthanized approximately one year after symptoms first appear.

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