[Belle Noir]

Yes, indeed, even though a dog may test clear of something, doesn't mean it's not carrying something in it's line.
My second litter was a full sister to my first breeding bitch. I got her in whelp. When she birthed, she managed to drop 4-5 puppies without me being there, one getting crushed, an all white female.
Never again did she have a puppy of that color, or even mostly white. But her litter sister (whom I owned before I got this bitch) managed to have a puppy (interestingly enough, always female) with a large amount of white in every litter.

Fast forward.. A male from Roxanne's line, again, flashy marked, was bred to a female from her sister's line, a white headed bitch, BEARed clear. That litter had several all white pups, one of them being deaf.
That same male was bred in short order to two other females, also from the sister's line, and each litter had solid white, deaf pups.

Mind you, I did not own the male, though I did own one of the females, and thought it would be a good breeding, as the deaf status of the male in the first litter wasn't know.

It went something like this, white head bitch was bred.. she whelps, a few days later, second bitch was bred. She whelps, and a few days after that, my bitch was bred.. So the first litter was at best 8-9 weeks.
Because of the influence of the littermates, it wasn't know that the first pup was deaf until he had been sold.

Then we tested, and though EVERY one of the parents was clear, there was 90% bilateral deafness in the spotted pups, and 50% unilateral deafness in the solid colored pups.

All I could do was hearken back to that one white puppy that was dead when I found her, and because this male had been bred to females that were related through a littermate sister to the mother of Roxanne, I knew it was something in the line that never popped up until then.

I ended sterilizing all the stock I had from that line, keeping the deaf pups, and warning everyone that had ever bought pups from me that were still intact from that line what we had found.

Now some will blame the line breeding, and that may well have been the case, but I am glad it became known first with me, as it was my line.

However, there is No Eyes Annie. A friend bought her, and she was a complete outcross. Nothing in the pedigree was remotely related until you got into the 12th generation.
And she was born with no eyes.
Her breeder didn't even realize it. I came over to test the litter, and I was shocked that this puppy was so tiny and underweight, and his response was, oh, she's the runt. When I examined her, I was like, no.. she's BLIND and can't find the food.
Her eye sockets were completely empty.
Her breeder gave her to me, (under a breeding contract, but I was desperate to agree to anything to get her to a vet.. Little does he know she would have never been bred, ever) I took her to the vet the next day, and he was afraid to do anything, because she was soo tiny and underweight. I actually started to bottlefeed her, even though she would eat food in front of her, especially not having any competition.
Sadly, a few weeks later, she died. But to this day, I wonder what were the circumstances that caused her to be born with that defect.

While some diseases are clear cut, there is also the issue of environmental causes of disease and structural fault. You may have a dog that comes from 6 generations of OFA Excellent hips, and feed that dog wrong, and you'll not have the hips that dog is bred for.
I recall a nice little bitch fed substandard (IMO) food. She had the flatest ricketiest feet I have ever seen. Yet her littermates all had nice tight feet.

It takes integrity to admit to issues within your breed, and more so within your line. Some years ago I was talking to a nice couple with a very familiar looking dog. I asked about the breeding, and sure enough, he went back to my old line. In fact, was bred by one of my buyers. I asked them if they were told about the deafness that popped up, and no, they were not.
Since deafness is a KNOWN problem with cousin breeds, breeders of this breed SHOULD be looking for and breeding away from possible deaf dogs, but if you ask the top breeders, THEY will say oh, this breed isn't known for that, so we don't bother.
It is like a child sticking their fingers in their ears and saying, "Na na na na I can't hear you." (no pun intended).

There is a highly bred, very popular bloodline that is KNOWN to have heart mummers, but the breeders of this line and the crosses of this line act as though it doesn't exist. Every year you hear of dogs from that line "dying of heat stroke," in the shade, with plenty of water. Particularly YOUNG dogs under 5.
It's not heat stroke, though it may play a part, it's heart failure, exacerbated by the heat, because they were bred down from a blue tongue bitch and her VERY popular full and half sibs.

In the end, it is the choice of the breeder what they chose to divulge about their breed and their lines. Yes, I took a great loss in sterilizing my line. But for me, it was the only thing I could do. EVERY dog traced back to that bitch or her litter sister, or their half brother (same dam).

No Eyes Annie's sire and dam continued to be bred and in fact, there was a repeat of the breeding that produced her. Thankfully, another eyeless puppy wasn't born, but that was the risk her breeder chose.
I would not say he had less integrity than I do, we're just different people. I am not the type to care much what other people think of me, so long as I can think well of myself, doing the right thing, not for backs on the back, but because it is the right thing to do.

To this day, there are Cavalier breeders that insist they have no incidence of Syringomyelia in their lines. But then again, they don't test for it either (granted the only sure way to test is an expensive MRI, but would you not do it?). Or Boxer breeders that say we don't have cardiomyopathy, but again, they don't test for it.

To which mind, I think the links idea of open health registries would be a wonderful idea. Of course, it only works if the breeders want it. Like when OFA first began, and HD was such a dirty secret. Or (please bear with my memory), how a study was done on either Akbash or Kangal litters, in comparison to the other and Anatolians. And one of the the first two mentioned had distinctly smaller litter sizes. The issue being that this breed (at the time, we're talking a good 15 years ago) supposedly ONLY came in either all white, or all fawn, and breeding true for only that color marked this dog as a pure bred, otherwise it was an Anatolian. (I really want to say it was the Kangal).
Well, the study concluded that there must be culling going on of mismarked/colored puppies, because they were not standard due to the extreme difference in litter average (5-7 pups as compared to 8-12 if I remember correctly, and these are a giant breed, 8-12 is what you should expect from a 90 plus lb bitch).
(The funny thing being, my research showed that the Kangal, Akbash and Anatolian are all the same breed, and are a landrace breed of guardian dog of the Turkish area, however, we (the West) arbitrarily decided that dogs from this area were one breed and dogs from this other area was another and dogs from this other area yet a third.)
Until there was a market and demand for them, Boxer breeders were known to "bucket" white pups, because if it were known their line threw mismarked dogs, they were afraid they and their lines would be stigmatized, though the breeding FOR flashy dogs (which is what usually wins in the show ring) promoted the production of whites.

If we could only be truly honest, not only with ourselves, but with our fellow breeders, and more importantly, to the public, it can only better the health of the dogs as a whole. But I am not sure that many of us are ready to say, this stud produced a dd puppy, so this is something to be aware of, and several of the pups produced by this bitch has luxating patellas from several litters. Or the presence of keratoconjunctivitis, or retinal dysplasia in the pedigree.
And the reason many of us are not willing to admit to these things are because of the reasons set forth by the linked article.