Sick Australian inbreeding family

I think I said that this sort of thing never happens. I stand corrected. It happened in a strange Australian family:

Not only were the Colt family closely related by generations of incest. In fear of discovery the appalling facts about their family, the Colts had fled three other Australian states before coming to rest in rural NSW.

And it was here that four generations of interbreeding exploded into a life of depravity.

Under the eye of the family matriarch, Betty Colt, who slept in the marital bed with her brother, the children copulated with each other and with adults.

Years of interrelations had resulted in some of the children misshapen and intellectually impaired. Many of them could not speak intelligibly.

They were profoundly neglected, to the point they didn't know how to shower or use toilet paper, and were covered in sores and racked with disease.

Left to their own devices, brothers with sisters, uncles with nieces, fathers with daughters, they engaged in sexual activities. ...

When they finally managed to get test swabs into a laboratory, geneticists uncovered a family tree which was a nightmare of "homozygosity", when a child's parents are closely related.

Eight of the Colt children have parents who were either brother and sister, mother and son or father and daughter.

A further six have parents who were either aunt and nephew, uncle and niece, half siblings or grandparents and grandchild.

Interviews with the Colts revealed the family saga began back in New Zealand, in the first half of last century when June Colt was born to parents who were brother and sister.

This will be a textbook example of how too much inbreeding can be bad.