Patient 3: heterozygous pathogenic ATM GV
Patient 3 was seen by dermatology at age two for a temporal lesion which started to thicken. The lesion was diagnosed as a spitzoid nevus and observed until the family requested removal. A shave biopsy confirmed SM. WLE and SLNB were performed with one positive LN. Treatment was surgery only and patient has been disease-free for three years. Germline testing identified a maternally inherited ATM pathogenic GV. Although the ATM variant is silent, experimental studies have demonstrated a splicing effect that results in skipping of exon 14.3,4 Cascade testing informed care of the patient’s mother, who was recommended to initiate breast cancer surveillance with mammograms with consideration of tomosynthesis and breast MRI with contrast starting at 40 years old or 5-10 years before earliest age of breast cancer diagnosis.5