Dr. George G. Glenner, a leading researcher into the molecular structure of the protein amyloid and its relation to Alzheimer's disease, died on Wednesday at his home in San Diego. He was 67.

The cause was systemic senile amyloidosis, said the Medical School of the University of California at San Diego, where Dr. Glenner was a senior scientist. Systemic senile amyloidosis is a rare disease caused by the protein amyloid, a form of which is also linked to Alzheimer's disease.

The existence of amyloid, which derives from the Greek word meaning starch-like, had been known for well over a century, but its properties remained a mystery and it was considered a medical curiosity. Dr. Glenner and a few colleagues began to explore its nature and functions in the 1960's.

Amyloid turned out to be a protein that plays a role in producing senility, which forces hundreds of thousands of the elderly to live under custodial care. Dr. Glenner pointed the way to molecular biologists in 1984 with a seminal publication in which he analyzed the purified beta amyloid protein linked to Alzheimer's disease.