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M-mode representation of the DCM. The heart muscle shows a contraction of about 10% (normal:> 25%) and is strongly enhanced -> Declaration trip to the genetics of different transmission modes: There are different inheritance paths: a) autosomal dominant: the affected gene was not on the sex chromosome, this inheritance is sex-independent, and because of their dominant character, it is sufficient if one parent transmits the disease-causing gene, so that the puppy is sick, too. b) autosomal recessive: this inheritance is also independent of gender, but because of the recessive character, both parents have to transmit the disease-causing gene so sick of the descendant. Transmits only one parent, the disease-causing gene, the puppy is only an intermediary: that is, he can pass the gene to his offspring, is itself but healthy. c) X-chromosomal inheritance: Every individual has two Geschlechstchromosomen: females have two X chromosomes, males have one X and one Y chromosome. That's the whole difference between the two Sex! In this mode of inheritance, the disease-causing gene is located on a sex chromosome, usually the X chromosome, because the Y chromosome does not contain many genes. The behavior of dominant obtain recessive remains, but the Vererbungsweg is different: here the sex of the animal it is important whether it is sick or not. Since we know that male beings have only one X chromosome, it is easy to understand that a dog is not a disease-causing gene on this chromosome only accessible even to be ill, but also that he inherited this gene to all his female offspring is! Females always have two X chromosomes, so for them it is more complicated: In the case of an X-dominant inheritance, ranging from a single infested chromosome to have to break the disease. In the case of a recessive X-inheritance, animals are infected with only one X chromosome healthy carriers: they themselves are healthy but can transmit the disease-causing gene. A mother with two affected X chromosomes is itself ill and will pass on the disease-causing gene to all their male offspring! Since every puppy has a double set of chromosomes (one from the mother, one from the father), male pups get the Y chromosome from the father, and the X chromosome from the mother. The female offspring of the same mother have a chance to be healthy if the father is healthy. Now back to the DCM in Great Danes: Man suspected an X-linked recessive inheritance. This means that females must be homozygous (they must have the allele on both chromosomes DCM) to suffer from DCM, while males become ill every time is on their X chromosome, the disease-causing gene. Since males have only so an X chromosome, they have "saved" by any chance the second chromosome to be healthy. This also means that a sick dog, the disease-causing gene to all his female offspring will inherit, as he has only one X chromosome inherited to: So you get 100% support in the female offspring. Now, if a sick dog mated with a dog, also an X-chromosome possesses the allele for DCM, we obtain statistically 50% of sick puppies! It is good to recall here that both male and female (homozygous) carriers of DCM, not at birth or even in growth can be detected: as I said, the disease often breaks out only in the adult animal. Important in terms of numbers and percentages of the term "ill": The sex ratio of female and male pups in a litter is completely random! is inherited also the frequency with which a sick-making allele ... the percentages are so purely on the statistical possibilities that exist in the recombination of the genes of both parents. Ultimately, in The reality is that union composed exclusively of male pups, or just for "sick" puppy, or vice versa, is usually due to chance is there in a litter of "a little bit of everything", but the distribution within the schemes described in the possibilities! The simplicity halberals "sick" means: a male that carries the disease-causing allele for DCM, and a dog that is homozygous for this allele (black solid colored symbols) in the knowledge that DCM is a progressive disease whose initial symptoms are insidious , it might have been correct, the term "genetic carrier of DCM, with early or later disease outbreak" to use, but that would have been a little long ... It seems to me important again to point out that quite a "clinically healthy" dog with "good faith" could be used for breeding, if the breeder is not about DCM enlightened this dog, but only a few years later developed a genetically predisposed DCM! This dog is how I see it as "ill". 6. Research program for the DCM, how can you participate? There are investigations underway, to clarify the exact cause of DCM in Great Danes, and to develop a test method for diagnosis. To push this research forward, it would make sense that as many Danes participate, and, above all, that undergo the breeders breed their dogs to the test ... in Sweden was quoted in a German population study of the Great Dane as the cause of death DCM No. 2, after the stomach twists and ahead of cancer. For Germany, there are still no numbers. There is no study on health and heart disease was previously unknown. A cause of death statistics are not published by the purebred dog breed clubs at the moment. A private statistic from Germany revealed a distribution of 65% of affected males compared to 35% affected females. This affects all color varieties. The average age of diagnosis was approximately 5.5 years, the average age of death was 6.7 years. The inheritance of DCM after a Study from the United States with the highest probability as x-linked recessive adopted. In humans, for example, hemophilia is inherited in this way. That is, in short: • is a dog falls ill, he may have gotten the sick gene only by his mother • is a bitch ill, she must have gotten the sick genes from both parents • Females can also be phenotypically healthy carriers. You will never be sick (because they have received the defective gene from one parent), but it can pass on to their offspring. In the United States since early 2006, research on a genetic test to identify carriers of the disease early enough. This is very important for the breed! This research can help any holder Dogg. It only takes a meaningful heart ultrasound and a saliva sample. In addition, a short questionnaire to be filled to the dog. And I'm happy to help. To participate in the research on genetic testing? Booyah! Short email to me enough, I then put in touch with you to resolve the rest. Sample support, questionnaires and the address of the university in Texas you get from me. What does DCM for the future of the Great Dane? If nothing happens: • Carried on carrier females remain undetected not bear their genetic defects in subsequent generations ... • heart stud also examined their genetic defects in subsequent generations ... • die still many German mastiffs an unnecessary and often unrecognized cardiac death ... What can you do? • Participate in the genetic test research. • If you are breeders, please consider a scan of your breeding dogs (even of the stud dog) to. • Find out more. • Inform others. And if you have any questions, I am happy to answer them ready to grais@live.de 
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