Her dermatologist noticed the freckling under both arms first. Combined with more than 10 café au lait macules scattered across her arms and legs, at least 10 of them measuring 15 millimeters or more, the picture pointed in one direction. Those two findings sit inside the formal diagnostic criteria for neurofibromatosis type 1.
She was referred to clinical genetics at age 56. Testing for NF1 came back negative. So did testing for SPRED1, the gene behind Legius syndrome, an NF1 lookalike. The appearance still fit. The genetics did not.
