Although scientists were divided over phytic acid’s nutritive value, proponents like Sabin pointed to its role as an antioxidant. With this strength in mind, he sat down at his typewriter and began tapping out an argument for full-fledged animal studies to examine phytic acid’s potential for protecting against heart disease and cancer. He sent his proposal to the Linus Pauling Institute of Science and Medicine in Palo Alto, California, and hoped for good news.
A positive answer arrived quickly. “They said I could do the work if I could fund it,” Sabin recalls. He arrived at the institute in the summer of 1984 for a crash course in laboratory protocols and then got down to work. Each project required armies of Fischer rats, the pink-eyed albinos widely used in biomedical research. Sabin wrote checks totaling more than $100,000 to get his projects off the ground. In one study, the object was to determine whether phytic acid could retard cancer in rodents. The results, published in Nutrition Research in 1988, showed reduced tumor growth rates in animals receiving phytic acid, but not in a control group. In a similar heart study, rodents dosed with phytic acid registered a drop in serum cholesterol of
32 percent and a decrease in triglycerides of 64 percent. That work, which proved the hypothesis that phytic acid could lower key markers for heart disease, was published in the Journal of Applied Nutrition in 1990.
Last January Sabin coauthored another study, his most gratifying to date, in the Journal of Alzheimer’s Disease. The paper grew out of research at the Oregon Health and Science University, yet another project involving phytic acid. Sabin donated $20,000 to the investigation, which also received substantially larger grants from the United States Department of Veterans Affairs and the National Institutes of Health. The study tested phytic acid in an Alzheimer’s mouse model and in a human cell line. The double-barreled study showed that phytic acid reduced the production of beta-amyloid protein, which is associated with the degenerative brain disease, and pointed to a possible new treatment. (A study currently under way in mice shows that phytic acid might be therapeutic for patients with Parkinson’s disease as well.) “I see myself as a medical pioneer,” Sabin says. “But I recommend that anyone who wants to do this think long and hard about it. You’ll mostly be working alone.”
Hugh Rienhoff’s attic office has provided a peaceful elevation from which to ponder in solitude the mutation that affects his daughter Beatrice—and what it might do to her as she grows older. Although he has achieved a measure of fame as a DIY gene-searching dad (he was one of the stars of a UCLA conference last year on “outlaw” biology), Rienhoff is by no stretch an amateur. Now graying and in his fifties, he studied genetics in the 1980s under the late Victor McKusick, one of the most accomplished medical geneticists of the last half-century. McKusick had once been part of a panel considering whether Abraham Lincoln might have been affected by Marfan syndrome, an uncommon genetic disorder involving the body’s connective tissues.
McKusick hadn’t been convinced, but after Beatrice was born, Rienhoff started wondering whether the rare syndrome could explain the constellation of symptoms affecting his little girl. In particular, his baby’s feet were especially long, a feature often associated with Marfan.
Concerned too that Beatrice never extended her fingers, Rienhoff and his wife took her to the first of many Bay Area specialists when she was 10 days old. It was a seemingly small deficit, yet Rienhoff and Hane worried that it was a sign of something deeper, possibly related to her apparent lack of muscle mass.
The doctor they consulted suggested Beals syndrome, a condition like Marfan but with less serious consequences. In the end, however, Rienhoff became convinced that neither diagnosis fit. Beatrice lacked the heart problems associated with Marfan as well as the constricted knees and elbows seen in Beals.
When Beatrice reached 18 months, her muscle mass still deficient, Rienhoff contacted colleagues at Johns Hopkins, then caught a flight to Baltimore, cradling his daughter in his arms. Certainly, he figured, doctors there would have a clue.
In the medical genetics department at Rienhoff’s alma mater, a colleague introduced him to Bart Loeys, an expert physician and geneticist who found Beatrice had a split uvula, the projection of the soft palate at the back of the throat. Rienhoff was not prepared for the diagnosis Loeys offered. “He said she had Loeys-Dietz syndrome,” Rienhoff says, referring to a genetic condition of the connective tissue named after Loeys and his Hopkins collaborator, pediatrician and geneticist Harry Dietz. A split uvula is a key feature of the condition, which, like Marfan, affects the heart, threatening to kill its carriers through a rupture of the aorta at an average age of 27 years. Marfan and Beals syndromes affect genes that code for fibrillin, a protein that helps form elastic fibers in connective tissue. In contrast, Loeys-Dietz is traced to a genetic defect in the TGF–beta (transforming growth factor–beta) signaling pathway. That pathway affects a vast number of cellular activities, including muscle development and myostatin, the growth factor responsible for muscle size.
Once again, though, Beatrice suffered none of the major deficits that normally come with a Loeys-Dietz diagnosis. The Hopkins specialists had some important insights, but Rienhoff felt they hadn’t nailed it. Back in California, he
concluded that if he wanted an answer,
he would have to dig for it himself.
Rienhoff started in 2006 by taking a blood sample from Beatrice and driving south to a nearby university, where a friend with a lab allowed him to centrifuge it, separating the blood’s components. The next step was purchasing a used thermocycler, a machine for amplifying DNA, for a little less than $800. The machine enabled Rienhoff to perform polymerase chain reaction, or PCR, a process that copies a minuscule tidbit of DNA up to a billion times. Ensconced in his basement, he heated Beatrice’s white blood cells in his thermocycler until the double-stranded helix of her DNA unwound, leaving single strands in its place. Primed by enzymes that Rienhoff added, the single-stranded molecules served as templates for building others, which were used to synthesize more single strands, en masse.
By repeating this process for hours, Rienhoff collected more than four dozen microliter ampules of genetic material, enough to send to a lab that sequenced Beatrice’s myostatin receptor genes, where he suspected the problem might lie. When the printout of that section of Beatrice’s DNA came back, Rienhoff found nothing that could explain her condition. So he broadened his search, asking another friend to sample Beatrice’s blood and sequence her entire genome, but even that information seemed to lead nowhere.
Night after night Rienhoff tediously compared his daughter’s DNA sequence with reference sequences stored in several major genomic databases—Ensembl, Heidelberg, and the UCSC Genome Bioinformatics gene bank, among others. Because of the Loeys-Dietz diagnosis, he focused particularly on genes in the TGF–beta signaling pathway, but nothing significant seemed to turn up. Last summer Rienhoff thought he had caught the culprit in a gene called CPNE1, but he quickly discarded the possibility because the mutation turned out to be too common to explain such a rare disorder.
Rienhoff dug deeper and studied harder, obtaining higher-resolution genetic data on Beatrice and comparing it with the genes of his entire family. He worked up from the roots and out to the branches of his small family tree, hoping to find a change in his daughter alone. Then, on an otherwise ordinary day last October, something extraordinary happened. Rienhoff found it: a mutation, a rare genetic miscue, the likely DNA signature of Beatrice’s lack of muscle mass. It was deep in the TGF–beta signaling pathway in a gene involved with uvula development. Why it hinders muscle growth is unclear, but it could interfere with production of myostatin in the womb.
Rienhoff is now rushing to confirm his finding and continuing to collect data in preparation for a paper he hopes to publish in a major scientific journal. He is also trying to puzzle out the mechanism by which the mutation affects his daughter’s muscles and joints. “The mutation Bea has could be unique in her genome,” he says, “but we will be looking for other cases, and I think we’ll find them.”