A 24 year old male presents feeling tired all the time. There are no other specific symptoms of note. Past medical history is unremarkable and he is not on any medication. Examination is essentially normal except for a blood pressure of 166/94. Blood tests reveal the following: Potassium 3.2, creatinine normal, urea normal. All other TATT bloods are normal. Which one diagnosis is most likely at this stage?
