Family History and Familial Inheritance, Risks

Family history is typically used to steer healthcare providers in the direction of possible health risks to a patient based on causation from health problems that affect the patient's family. Families tend to eat the same and are similarly active. Their habits are also similar among other family members, and families share genetic inheritance from previous generations.

If your grandfather had heart disease and your father had heart disease, you need to be screened for heart disease. A woman whose mother had ovarian cancer and whose grandmother had ovarian cancer may want her own ovaries removed after childbearing.

Mendelian inheritance refers to the expression of traits over two or more generations in a family with parental-to-offspring transmission (autosomal or sex-linked, dominant or recessive)

Autosomal disorders:

• Autosomal dominant abnormalities: 1:2 children will be affected.
• Autosomal recessive abnormalities: 1:4 children will be affected.

Sex-linked:

• X-linked dominant: males more likely, due to an unopposed X-chromosome in an XY genotype.
• Y-linked dominant: males only (females have no Y-chromosome).
• X-linked recessive: Males only (with XY); girls have 2 Xs, which in any recessive situation with one of them being normal means no disease (although they may be a carrier).
• Y-linked recessive: does not occur.

Aging and age-related disorder considerations are another way to predict possible health concerns for a patient or groups of patients.

Example: Elderly patients are more susceptible to fractures resulting from falls.

Immunologic disorders based on common familial diseases are often familial or have increased risk for a patient based on their family history. They include:

• allergies,
• asthma, and
• rheumatic inflammatory diseases.

Breast, colorectal, and lung cancer as well as other cancers, are often familial or have increased risk for a patient based on family history.

A particular inherited genetic predisposition is associated with the BRCA I & II mutations. These susceptibilities to cancer include: 

• uterine,
• ovarian,
• breast, and
• gastrointestinal cancers.

The familial association is so strong that daughters of women who have ovarian cancer are often counseled regarding prophylactic removal of ovaries and uterus after childbearing is complete.

Also, if there is GI cancer in a male family member, this association makes it more likely that female members are at risk for uterine, ovarian, and breast cancer.

Endocrine disorders such as diabetes (type 1 or type 2) are often familial or are at increased risk for a patient based on family history:

• diabetes I & II,
• thyroid disorders.

Hematologic disorders are often familial or racial, or they have increased risk for a patient based on family history:

• hemolytic anemia,
• hemophilia,
• hemochromatosis,
• leukemia,
• Sickle-cell anemia,
• thallasemia major, and
• pernicious anemia (vitamin B12 deficiency).

Cardiovascular disorders are often familial or have increased risk for a patient based on family history, but are also based on noncausal findings.

• arrhythmias (long QT syndrome, Wolfe-Parkinson-White syndrome, Wenckebach, and other cardiac pacemaker abnormalities of the sino-atrial node),
• cardiac myopathies,
• mitral valve prolapse,
• coronary heart disease,
• hypertension, and
• stroke.

Renal disorders are based on both familiar history and noncausal findings:

• gout and
• kidney stones risk.

GI disorder risk is based on both familial history and noncausal findings:

• malabsorption disorders (lactose intolerance, ulcerative colitis, Crohn's disease),
• peptic ulcers,
• gallstones, and
• obesity.

Neuromuscular disorders are often found to have no correlation with family history, but if family history is confirmed, it proves critical in evaluation:

• Huntington Disease,
• Muscular Dystrophy,
• Multiple Sclerosis, 
• ALS, and
• Alzheimer’s Disease.

Psychiatric disorders are often familial or have increased risk for a patient based on family history:

• schizophrenia and
• manic-depressive disorder.