5th April 2024

An 8-year-old boy is referred to Endocrinology outpatients after presenting to his GP with extreme muscle weakness following a sports day running event.

An 8-year-old boy is referred to Endocrinology outpatients after presenting to his GP with extreme muscle weakness following a sports day running event. His mother explains he finished the race in first place and was resting, sitting on the grass, eating a banana, when he started shaking uncontrollably. There was no loss of consciousness but after the episode, he was unable to stand and she carried him to the GP practice where they took blood tests and assessed him. His blood results from the time are available for you to review and show a potassium of 6.2 mmol/L and a raised haematocrit.

On further questioning, his mum recalls a similar event when her son tried to fast during Ramadan but she put it down to hunger and made him break his fast. She is concerned because the boy’s father, who she is separated from, had similar problems and was diagnosed with a medical condition. You suspect this is an inherited condition with a mutation on which gene? 

Select the SINGLE most appropriate option from the list below. Select ONE option only.