At the March 9, 2006, Pastfinders’ meeting, member Betty Morris presented information about
Chromosomes, Genes, and replication of DNA, transcription and translation of genetic codes, as
well as mitosis (cell division) and meiosis (sex cell division resulting in 23 chromosome containing
sperm cells and ova). Chromosomal disorders such as Down syndrome, Turner Syndrome and
Klinefelter Syndrome were described. Autosomal dominant, autosomal recessive, X-linked
dominant, X-linked recessive and Maternal (mitochondria) inheritance patterns of single gene
inheritance were also described.
The purpose of presenting this information was to provide members with a basic understanding of DNA structure and function in the human body and in the passing of hereditary information from parents to child. The further purpose was to impress on members the importance of including any and all family medical history in their genealogy research for their own and their descendants’ benefit. Cause of death in death records past and present is often misleading. Many deaths attributed to heart failure doubtless had other contributing causes of greater significance that are not given. Anecdotal evidence describing symptoms or behavior needs to be recorded and noted as such. Patterns of disease or conditions that result from this information may reveal a hereditary problem that needs investigation for the present living family members to guard their own health as well as those of future children born to the family. Such conditions as difficult childbirth, miscarriages, stillbirths and any related problems should be noted. Deaths of children may be related to epidemics of such diseases as diphtheria. measles, whooping cough, polio and the like which are rarely such a problem today, but still need to be noted. Hearing and vision difficulties should not be overlooked as some of these may be hereditary conditions. Diabetes Type I and Type II, heart disease, stroke, and breast, colon, and prostate cancer, Alzheimer Disease, Huntington Disease and Parkinson Disease are but a few conditions that come immediately to mind to annotate and to date in terms of the age at which diagnosis was made. There are many other genetic diseases and disorders. If in doubt, look the disorder up and include it in you family medical information.
Of great importance is the recognition that certain cancers are hereditary, not just the also important tendency for family members to develop them later in life, but to be born with them. Retinoblastoma in infants, Wilms Tumor, Familial Adenomatous Polyposis, Neuorblastoma, and several others may be present at birth and may require immediate treatment if the child is to survive.
Also of great importance is to be aware that certain conditions may arise in certain racial groups and seldom or never in other racial groups. Sickle cell anemia, high blood pressure, Tay Sachs, and many other hereditary diseases and syndromes have higher incidence in particular racial groups.
This situation is likely do to mutations in certain genes due to some environmental factors, such as malaria, to which entire populations were exposed over time.
One item we did not have time to cover was the matter of occupation of forebears. My own paternal grandfather had a bizarre breakdown of body functions in his 50’s which was a mystery as well as a worry at the time. I have learned that he was a pressman (printer) and I suspect that exposure to benzene or other chemicals used in earlier times in inks and other mass printing operations had this deleterious effect on him. So keep your mind open to the possibility that occupational hazards were not known years ago and may have contributed to health problems and early deaths which often were caused by pneumonia which was secondary to another underlying problem.
We have skimmed the top of the iceberg in regards to genetic disorders in that there are 6000 known single gene disorders, most of which are rare, but have significant combined impact. Genetic counseling may be needed when there are significant known risks of passing a serious genetic defect on to the next generation.
Collect all the family medical information that you can. If in doubt, include it as it may be relevant when additional information comes to light.