Building Your Family Tree

The most useful diagnostic tool in monogenic diabetes costs nothing. It is a properly constructed family history, and patients are much better placed to build one than doctors are.

What you are looking for is a pattern: diabetes appearing in roughly half of each generation, diagnosed young, often in lean people, passing from parent to child rather than skipping around.

Go back three generations if you can. For each relative, try to note four things: whether they had diabetes, roughly what age they were diagnosed, what treatment they were on, and whether they were slim or heavy at the time.

Treatment history is more informative than it sounds. A grandmother on tablets for forty years without progressing, or an uncle who was called Type 1 but managed on very little insulin, are both suggestive.

Ask relatives directly. In Indian families this information often exists but has never been assembled in one place — one aunt remembers when her father was diagnosed, another remembers what he took.

Write it as a simple diagram: your grandparents at the top, their children below, then your generation. Mark who had diabetes and at what age.

Take that diagram to your appointment. A clear three-generation pattern is frequently what converts a doctor from "probably Type 2" to "worth testing".