Rimoin was also among the first to recognize that diabetes is caused by a variety of genetic abnormalities and he played an influential role in establishing screening programs for Tay-Sachs disease.
An earlier version of this obituary said Dr. David L. Rimoin recruited Dr. Michael M. Kaback to Cedars-Sinai Medical Center in 1970. Rimoin recruited Kaback to Harbor-UCLA Medical Center, where he began working in 1970. Rimoin joined Cedars in 1986.
"We have lost a giant in the field of medicine," said Thomas M. Priselac, president and chief executive of Cedars. "Children, adults and families from across the country and the world who turned to him for his medical expertise have lost a uniquely skilled and caring physician who was singularly devoted to their health and well-being."
Rimoin was a fellow at Johns Hopkins University in Baltimore in the 1960s when he encountered a woman who was in the hospital to have a mitral valve in her heart repaired. She was about 4 feet tall and looked, he said, like a pituitary dwarf, with wrinkled skin and a high-pitched voice. But unlike pituitary dwarfs, who are deficient in all hormones produced by the pituitary gland, she was sexually mature and had a daughter who was normal-sized.
Rimoin used the then-new assay for human growth hormone and found that was the only hormone she was missing. The discovery began a lifetime of research examining dwarfism and other skeletal defects. He traveled to circus sideshows and little peoples' meetings to collect blood samples and persuaded many of them to undergo a rib biopsy to provide bone samples as well.
In 1970, he established the International Skeletal Dysplasia Registry at Cedars to provide a source of data and diagnostic consultations for people with bone and cartilage disorders that affect the growth of the skeleton.
While he was still at Hopkins, Rimoin reasoned that African Pygmies might also suffer from a growth hormone deficiency. His mentor, Victor McKusick, contacted Luigi Luca Cavalli-Sforza, who was doing population genetics work in Pygmies in Africa. Cavalli-Sforza told Rimoin to be in the Central African Republic village of Bangi in two weeks.
Collecting a variety of necessary medical supplies and liquid nitrogen containers (that had been developed to collect bull sperm in the field), Rimoin reached Bangi on schedule and began negotiating with the Pygmies and the Bantu (who treated the Pygmies as slaves) to collect blood samples.
Back in Baltimore, Rimoin and his team found that the Pygmies had normal levels of growth hormone, but had unusually low levels of glucose, insulin and fatty acids. He ultimately showed that the Pygmies were resistant to the effects of growth hormone. A second trip to Africa to collect samples from the Bantu showed that this condition was genetic, not environmental.
For his research, Rimoin has been named an honorary life member of the Little People of America.
Shortly after he arrived at Harbor-UCLA Medical Center in 1970, he recruited Dr. Michael M. Kaback to join the medical center. Kaback, now at UC San Diego, developed a blood-screening test for Tay-Sachs disease, a lethal genetic disorder that was common among Ashkenazi Jews. The disease is characterized by the accumulation of cell-membrane components in nerves, leading to deterioration of mental and physical abilities. There is no treatment and the disorder is deadly by the age of 4.
Kaback and Rimoin organized the California Tay-Sachs screening program, which allowed the identification and termination of fetuses with the disorder. That program became a model for nationwide screening programs and has led to the virtual elimination of the disease.
David Lawrence Rimoin was born Nov. 9, 1936, in Montreal and raised there. He enrolled in McGill University at the age of 16, then continued on to McGill's medical school, receiving his medical degree in 1961. During his fellowship and residency at Hopkins, he also obtained a doctorate in human genetics.
During this period, it was not recognized that there were two major forms of diabetes, now known as Type 1 and Type 2. There are also several different forms of Type 2 diabetes, which strike different populations.
For his doctoral thesis, Rimoin collected information about the disorder and concluded that diabetes was a heterogeneous group of disorders and not just a single one as had been believed. Diabetologists scoffed at his conclusion, but within 10 years his findings were upheld by a variety of research.
In 1986, he joined Cedars and established an adult genetics program at the hospital to provide comprehensive risk assessment for a variety of adult-onset diseases, including cancer, heart disease, diabetes and stroke. More recently, he established a unique genetic screening program to test for four common inherited disorders within the Persian Jewish population, which numbers more than 20,000 in Los Angeles.
Rimoin is survived by his second wife, the former Ann Piilani Garber; two daughters, Anne and Lauren; and a son, Michael.
The family is planning a private funeral and a public memorial.