2.2 | DNA sample collection and extraction
The probands were patients at the School and Hospital of Stomatology,
Hebei Medical University. Peripheral blood samples were collected using
EDTA as anticoagulant. DNA was extracted from leukocytes using standard
proteinase-K phenol chloroform methods (E.Z.N.A. Blood DNA Midi Kit,
Omega, GA) and stored at -20°C.