A GP’s son has appealed to doctors for help solving the mystery of his mother’s disappearance, after the family discovered she was diagnosed with a serious illness before she vanished. 

Dr Nathalie Casal was last seen alive at her outer Perth home on 6 December, where she said she planned to hike the 1000km Bibbulmun Track in WA with an organised group. 

But the 71-year-old has not been seen for four-and-a-half months.

Her family reported her missing in March when she failed to make contact as planned.