GSD Dwarfism - a brief history

Brief History of Pituitary Dwarfism

I find it particularly interesting that I cannot find any references to dwarfism in early breed books and articles, and especially that I cannot find a reference in von Stephanitz since he was usually forthright about breed defects.

Dwarfism was probably first documented in Germany around 1952 resulting in the Moch & Haase (1953) paper. This was a thorough investigation at the University of Hannover of a GSD dwarf around 11 months old, 34 cm at the shoulder, weighing 6.1Kg. Due to the usual research/publication delays we can assume this dwarf was born in 1951. This paper also contains the first published photographs I have been able to find.

The pathology in this study was good and the paper shows clearly the same anterior pituitary hypoplasia and cystic damage we find with monotonous regularity today - over 50 years later.

The next serious studies into multiple GSD dwarfism took place in the late 1960's and throughout the 1970's with the majority of the work being done in Denmark at the University of Copenhagen and in Australia at the University of Sydney. Both countries experienced a sudden explosion of dwarfism into blood lines which had not previously displayed this condition. The common factor in both cases turned out to be related to recent imports from Germany and, in the case of Australia, also from the U.K.

In Denmark dwarfism was also studied in the Karelian Bear Dog (known as the Carelian Bear Dog in Finland) which displayed a virtually identical pathology and inheritance pattern. The theory put forward to explain this was that the Karelian Bear Dog had been crossed with the GSD during the early 1940's to 'harden' the breed and the belief was that the gene(s) responsible had been introduced from the GSD. If this is true then it shows two important things:

1. that the defective genetic material was in the GSD breed about 10 years prior to the Moch and Haase paper, and

2. that the defective genetic material is clearly heritable not only within a breed but also across breeds. There is at least one recorded instance of a dwarf GSD-cross which also tends to confirm this.

Genetic studies in both Denmark and Australia based on segregation analysis of affected litters suggested in both countries that the condition is inherited as a simple autosomal recessive - that is to say that BOTH parents are carriers of the defective gene and that 50% of their progeny will also carry the defective gene, and so on, until they are removed from the breeding programme.

Retrospective pedigree analysis in both countries suggested the same possible source dogs. Regrettably, the nature of inbreeding in the GSD renders their conclusions to be inevitable since the same common ancestors occur in pedigrees all round the world within a few generations. We have exactly the same problem with dwarfism retrospective pedigree analysis today - only the names are different... While the names are different, they are all in direct lines of descent from the possible source dogs identified previously.

By the 1990's dwarfism appears to have spread to virtually every country in the world which imports breeding animals. Significantly, I can find no reports of outbreaks of dwarfism in closed populations of GSD's. What is clear in virtually all cases is that animals (both sexes) exported from Germany, and German bloodlines exported from other European countries (including the U.K. , Belgium, Denmark, and The Netherlands), are deeply implicated in the spread of dwarfism around the world and this has been happening for over 50 years while the information on dwarfism coming out of Germany has remained constant at just over zero.

One traditional excuse in Germany for defects like dwarfism has always been to blame 'foreign bitches'. However there is now multiple evidence of dwarfism resulting from the mating of all-German quarantine-born and exported German VA and V graded males with exported German V graded females so we have to assume that a parallel situation exists within Germany and that it has done so over the same 30-50 year period. All the available evidence therefore suggests that a conspiracy of silence exists in Germany.

Bio-medical studies into dwarfism, and attempts to treat surviving dwarfs to improve their condition, have always been hampered by the fact that most of the relevant hormones are species-specific. This means that human medical diagnostic kits will not give reliable results and treatment with human, bovine, porcine and synthetic hormones also has minimal, if any, effect. New canine-specific diagnostic tests have become available in the last few years and they are now being used to gain new information and to confirm what has been found already using a variety of quite ingenious bio-medical methods.

New methods of treating dwarfs have also become available in the last few years though it is clear that the prognosis for the vast majority remains very poor indeed.

The future is in canine DNA analysis and this is the only way we are going to find the true key to the inheritance pattern. A combined German and Dutch endocrinology paper published recently confirms, using more modern methods, previous findings that the adrenal function remains minimally affected in GSD dwarfism thus narrowing the range of cell-types and developmental genes which need to be investigated for malfunctions. Once the genes are identified it should be possible to produce a DNA diagnostic test which will enable ethical breeders to select against hypo-pituitarism in the GSD.

I now have reports of dwarfism in 26 countries ranging from Australia to Zimbabwe. It is very difficult to put a figure on the occurrence but the figure I have come up with is that the breed is now losing 1 in 200 puppies to hypopituitarism from within the surveyed/top-end of the breed, most of which is not showing as dwarfs but as stillborn and fading puppies.

The concept that 'dwarfism' is happening without actually seeing any dwarfs is quite a difficult concept for breeders to grasp. There is clear evidence from within the scientific studies and from breeder reports that still-born and fading puppies are found with dwarfs but there has been very little research done on the still-born and fading puppies simply because they have been disposed of by the time the dwarfs become obvious. I have only been able to find one report of a post-mortem examination on a fading littermate and that did show the expected hypoplasia of the anterior pituitary lobe consistent with the dwarf condition. More research into the still-born and fading puppies is urgently required to clarify the position.

The incidence of dwarfism in the future depends on whether breeders are prepared to take the financial losses associated with removing known carriers from the breeding programme.

In the absence of any definitive evidence on the inheritance pattern, I believe that the recessive theory should be accepted pending clarification to prevent the possibility that 50% of the progeny from the highly used VA males will themselves return the defect to the breeding pool.

Based on the evidence I have accumulated over the last 10 years, it remains my belief that animals which produce dwarfs should have their Breed Surveys noted and they should be removed from the breeding program directly by the registration authorities by refusing to register their progeny. The precedent for this already exists with haemophilia A and I would like to see it extended to dwarfism.