Oldest evidence yet of a human hereditary genetic disorder found

The discovery of what is believed to be the oldest evidence yet found of a human hereditary genetic disorder has been announced by researchers at the Hebrew University of Jerusalem.

The researchers are Dr. Uri Zilberman and Patricia Smith, the Joel Wilbush Professor of Medical Anthropology, both of the Faculty of Dental Medicine of the Hebrew University and Dr. Silvana Condemi a senior researcher at the French Research Institute in Jerusalem. They are among the authors of an article in the June issue of the Journal of Human Evolution that details the finding of a disease known as amelogenesis imperfecta in the teeth of a fossil found in archaeological excavations in Ethiopia. The fossil is dated as 1.5 million years old and is from a two-year-old Homo erectus child. Homo erectus was a precursor of modern man.

According to Dr.Zilberman, this is the first recorded evidence from such an early prehistoric period of a hereditary disorder in which the specific genes responsible have been identified. Undoubtedly, he said, there are other hereditary diseases that have come down to us from prehistoric ancestors and which are yet to be discovered in fossil remains.

Amelogenesis imperfecta is a hereditary disorder that manifests itself in tooth enamel that is abnormal in structure, low in mineral content and hence subject to rapid wear and chipping. The Hebrew University researchers confirmed the clear presence of the disease in the fossil sample through x-ray and scanning electron microscope analyses. The disease appears relatively rarely today (one in 14,000 people in Israel, one in 8,000 in the U.S.). It is much more common in one area of Sweden (one in 700).