Transmission history includes family history and exposure history. It can now be specified and assessed throughout the program.
On the Start screen Transmission history is accessible from a button that is light green once an age and sex have been entered. The button displays a summary of what is known about transmission using the same convention as used elsewhere in the software, shown below as a green check mark for present. Other displays are a red X for absent and a black question mark for not specified.
Clicking the Transmission button displays the underlying details and allows you to make changes.
The Transmission history can be popped up wherever it is shown in the software. On the Add Findings tab it is shown when Transmission history could be useful in distinguishing diseases in the differential diagnosis. This is illustrated below in a differential diagnosis in which the most likely diagnosis is Achondroplasia, which has autosomal dominant inheritance and the next most likely diagnosis is Hurler syndrome, which has autosomal recessive inheritance. After adding the Transmission history details the effect of the changes in the differential diagnosis are shown.
When transmission history is displayed on the Explain Diagnosis screen the frequency with which a positive transmission history is expected is shown as a black bar to the right of the finding name. The figure below illustrates this in an autosomal recessive disease. If there is one older sibling one would expect a positive family history with a 0.25 probability. As shown below, for 2 older siblings, one would expect a positive family history with 0.44 probability (1.00 – 0.75*0.75). The calculations take into account not only the inheritance mode of the disease, but also penetrance, de novo occurrence of pathogenic variants and the degree to which an X-linked disease is dominant or recessive. The same detailed analysis is used in computing the effect of transmission history on the probabilities of each disease.
