‘The thing that really makes me stand out from the crowd is that I have Klinsmann’s disease,’ said Aiden.

He stood by the teacher’s desk, his hands clasped in front of him. He didn’t fidget and his voice was clear and steady. The words didn’t pour from his mouth either, like happens with so many kids. His gaze roamed the class, made contact with everyone.

‘This is a condition that affects one in approximately twenty million, though most people who have it don’t have it as severely as I do.’ He held up a hand. ‘But don’t worry. It’s not something you can catch by sitting next to me or by breathing the air around me. You’re safe.’ He paused and allowed the class to digest this. ‘Some of you might think that if I have this disease, then Ashleigh must also have it, since it is generally believed that identical twins have identical DNA.’ He looked at Charlotte as he said this. ‘But that’s not actually true. Sometimes, very very rarely, one identical twin can have a genetic disorder that the other doesn’t have. That’s because Ashleigh and I have different karyotypes and that means we are not genetically identical, though we are in every other way. I’m glad my sister doesn’t have this disease, because it’s not very pleasant to live with, to tell you the truth.’

He paused again. The class was completely silent and it occurred to me that, although Aiden tends not to say very much most of the time, he certainly knows how to use words when he does. He was keeping the audience guessing about what Klinsmann’s disease actually involves. Even Mr Meredith was leaning forward and concentrating and he must have known about Aiden from the medical records Mum and Dad had to provide the school.

‘I used to have to go into hospital every few months for treatment for this disease when I was younger,’ he said. ‘Now that I’m older I don’t have to go so often. Once or twice a year. And the surgeons put me to sleep and they operate, cleaning out almost all of my lower intestines.’

I glanced around the class. A few kids grimaced at the mention of intestines, but they were still fascinated.

‘You see, that’s what Klinsmann’s disease does,’ Aiden continued. ‘It makes it impossible for me to digest food in the way that everyone else can. I could eat an apple, for example, and it would just sit in my stomach. If I ate more, then I would start to feel very uncomfortable. Pain would follow. But most importantly, even with food in my stomach, I’d be starving to death.’ He smiled. ‘That’s not a very good thing, by the way.’ A couple of the kids laughed.

‘So this is what I eat,’ said Aiden. He pulled his dinner flask from his schoolbag and poured a small amount of mush into a bowl that Mr Meredith must have found for him. There was a collective groan of disgust as the green paste settled at the bottom of the bowl. Aiden picked it up and took it to the desk that Charlotte and I shared.