In Sobol v. State of California Department of Corrections and Rehabilitation, 2017 Cal. Wrk. Comp. P.D. LEXIS 454, the WCAB determined that an AME's opinion on apportionment to genetic factors was not substantial evidence because it was conclusory and not substantiated with sufficient medical rationale. The applicant sustained an industrial injury to his lumbar spine. The AME reported that the cause of degenerative disease in the spine was convincingly shown to be principally genetic, and apportioned 25 percent of the disability to cumulative aggravation from the job. The WCAB stated that although City of Jackson v. WCAB (Rice) (2017) 82 CCC 437 allowed apportionment to genetic or heredity factors, a decision must be supported by substantial evidence. The WCAB found that the AME made a conclusory statement that degenerative disk disease was convincingly shown to be genetic, but did not provide any medical detail, data, studies or research articles to support his findings. The applicant was awarded permanent disability based on the AME's opinion without apportionment.