Workers Comp Zone


How significant will the concept of apportionment based on genetics become?

Now that at least one California Court of Appeal decision has given the green light to apportionment to genetic causation, it is an issue being debated in the California workers’ comp community.

At the recent 2018 CAAA winter convention at Rancho Mirage I moderated a panel on the genetic apportionment case, City of Jackson v. WCAB (Christopher Rice) (see link to the case at the bottom of this post). Joining me on the panel were Sarah Carr, an applicant attorney, Richard Jacobsmeyer, a defense attorney, and a pain management specialist and QME, Dr. Jacob Rosenberg.

Is Rice a “game changer” that could lead California into an era of very ugly inquiry about genetics of various racial and ethnic groups and an era of dueling genetic studies and genetic experts? Or is it a more benign case that if read properly simply gives doctors some extra ammunition to apportion causation to preexisting degeneration and other progressive underlying pathological conditions?

Will workers’ comp attorneys need to become much more familiar with genetic concepts and studies? Will QMEs shy away from these genetic concepts lest they make themselves controversial? And will the courts demand a high degree of analysis or simply rubber stamp opinions based on genetics? Will we see increased discovery disputes involving efforts to access family medical history or efforts to present scientific studies to doctors? These were some of the issues discussed by our CAAA panel.

Prior efforts to further codify prohibitions on genetic apportionment were vetoed by Governor Schwarzenegger in 2008 (AB 1115) and by Governor Brown in 2011 (AB 1155). Currently pending is AB 617 (Bradford), a bill which would exclude genetics and heredity from apportionment.

At the CAAA seminar I requested a show of hands for those who were dealing with genetic issues in their cases. Out of perhaps 800 attendees, maybe 10 hands went up. But is is early in the game, since Rice only came down last year.

One thing is clear: under Labor Code 4663 and the Escobedo and Brodie cases, the proper apportionment analysis is to causation of disability, not causation of injury. Escobedo and Brodie made it clear that the analysis of causation may be different for disability than for injury.

There is valid concern that under the Rice case many doctors could attempt to apportion based on the cause of injury (for example, the degree of genetic causation of degenerative disc disease) rather than the cause of disability. Pathology, even genetically linked pathology, does not necessarily equate to disability.

One problem fully analyzing Rice is that like so many appellate cases, the underlying factual record is not accessible. The QME reports and particular genetic “twin studies” referenced by the QME are not available as part of the court’s opinion. Further,  it is not clear what questions the applicant attorney asked on cross examination of the QME and whether other genetic studies were presented.

We do know that the issue of whether use of genetics in apportionment violated  Government Code section 11135 (California’s anti-discrimination law which includes genetic information as a protected class) was not raised at trial and that later briefing on that issue to the Court of Appeal was not entertained since it was not raised at trial.

As I prepared for the CAAA seminar  I pulled out my trusty “Genetics for Dummies” book, an introduction to genetics concepts to orient myself on some of the concepts.

CAAA syllabus materials included Wikipedia articles on The Twin Studies, articles on the concept of heritability from Wikipedia and the Stanford Encyclopedia of Philosophy, and a handful of academic articles raising questions about heritability estimates.

A look at some of the articles on heritability of particular conditions makes it clear that this field of population genetics is at the intersection of biology, mathematics and even philosophy. Behavioral heritability and heritability of IQ has been the subject of furious intellectual debates for decades and has at times taken on racialized overtones. More broadly, biological determinism has come under attack from a large number of critics.

It’s the old debate over nature versus nurture.

The problem with using some of the genetics studies as bases for apportionment of causation of disability is that the studies may be be misinterpreted and used in a manner for which they were not intended. This may well have happened in Rice, as the Court of Appeal notes that the QME in Rice claimed that “...degenerative disc disease in adults “may be explained by up to 75 percent by genes alone” and that “genetics or heredity was a major factor in all cases of degenerative disease”. This sort of analysis appears to go to the question of causation of pathology rather than of disability and appears to conflate the import of heritability studies by applying them to an individual rather than a population.

Generally, most heritability studies are looking at the proportion of the total variation in a given characteristic in a particular population that can be attributed to genetic differences between members of that selected population. Many commentators on heritability note that even if there is high statistical heritability, this does not mean that in the individual a particular trait or disease is inevitable. Other commentators note that heritability analysis is specific to measured specific populations and not applicable to any particular given individual.

Philosophers such as Richard Lewontin and Neven Sesardic have argued about the meaning and validity of genetic heritability analysis. One of the problems of heritability analysis is that heritability estimates seem to ignore the interaction between genetics and the environment.

In looking over some of the “twin studies” and other articles on heritability, I note that wide range of concepts are discussed. Here are some of them: “missing heritability problem”, “variance”, “epistatic interactions”, “phenotype plasticity”, “evocative effects”, “gene-environment interaction”, “additive genetics”, “non-additive genetic effects’, “genome-wide complex trait analysis”, “broad sense heritability”, “narrow sense heritability”, “quantitative genetics”, “biological determinism”, “correlation does not imply causation”, “SNPs (single nucleotide polymorphisms”, “high and low penetrance”, “expressivity”, “variable expressivity”,”extended pedigree design”, “reverse causality”, “epigenetic regulation”, “anticipation”, “genes controlling genes”, “jumping genes”,  “norms of reaction”, “environmental modifiers”, “dominance variation, additive variation and epistatic variation”, “shared and non-shared environmental factors”, “discordance”, “candidate-gene studies”, “stoichiometric ratios”, “study bias”, “polygenic”, “GWAS”, “causality theories”, “genotypes” and “phenotypes”, “norms of reaction”, “average allele effects”, “morphometric traits’, “heritability based on unrelated individuals of mixed ethnic backgrounds”, “Promethease”, “Mendelian sequence” etc etc.

Got that?

My point is that there is a lot to understand here. Before lawyers ,QMEs and judges start slinging this stuff around we may want to draw a deep breath and recognize that 1) yes, science is evolving but 2) the workers comp community should exercise great care and not become inured to reliance on a few genetics studies that may be poorly understood, susceptible to misuse and heavily criticized.

Escobedo and its progeny have allowed apportionment of disability to pathology in some cases provided the doctor explained the how and why in a non-conclusory way that met the substantial evidence standard. In a way, genetics may turn out to be a “red herring”.

Here is the opinion in City of Jackson v. WCAB (Christopher Rice):


Stay tuned.

Julius Young