‘There’s also the fact that the cornea transmits and focuses light into the eye,’ he went on. ‘And while that’s not directly comparable to the way in which Kenzie’s transparency is affected by light, both processes share the same fundamental principle of human cells interacting with light.’
‘But what does that mean?’ Dad said. ‘Are you saying that –?’
‘We don’t know what it means yet, Mr Clark. That’s what I’m trying to tell you. It might be nothing, it might be something. And it might just be the key to finding out what’s wrong with your daughter. And I’m sure you’ll agree that’s the only thing that matters.’
‘Of course,’ Dad said.
Of course.
The sequencing and analysis of Nan’s DNA was still in its early stages, Dr Reynolds explained. Part of the reason for the delay was that he’d assumed, given the genetic nature of her blindness, that Nan’s genome would already have been sequenced, and it had taken a while to find out that for some reason it hadn’t. It had also taken a while to realise that there was no communication between Dad and her, so she had to be contacted directly.
Dad had given his consent for gene sequencing to be carried out on himself as well as me, and although there was still a lot of work to be done, the basic analysis of both sets of results had already been completed. He’d also agreed to Dr Reynolds request to sequence my mum’s DNA.
I didn’t want to know how that had been done.
I didn’t want to know that her DNA had been extracted from tissue samples that had been retained after her post-mortem.
I didn’t want to know . . .
‘Is there anything in Mum’s DNA that shows why she died?’ I said.
‘We haven’t found any known abnormalities,’ Dr Reynolds told me. ‘What we have found though . . .’ He paused, frowning, scratching his head. ‘This is very difficult to explain . . . in fact, to be perfectly honest with you, we’re still struggling to understand it ourselves. All we really know at the moment is that four out of the five genomes we’re working on share a very distinctive abnormality that, as far as we can tell, has never been seen before. In all four cases it’s located in the same segment of so-called junk DNA, and the structure and form of the four mutations is very nearly identical. However . . .’
‘Whose is the fifth genome?’ I asked him. ‘The one without this abnormality?’
‘Sorry,’ he said. ‘I should have made that clearer. The four linked genomes are yours, your brother’s, your nan’s, and your mum’s. Your dad’s sequencing hasn’t revealed anything.’
I looked at Dad.
He shrugged, his face blank.
There was something in his eyes though, something vaguely familiar, and as he looked away from me – possibly trying to hide it – I wondered if he was beginning to feel a twisted sense of vindication. There was nothing wrong with his DNA, was there? If inherited genes were to blame for his children’s sickness, they hadn’t come from him, had they? And if they’d come from Mum, and they’d maybe even been the cause of her death, who had she inherited them from? Her mother, of course. Who else?
Or maybe I was wrong. Maybe Dad wasn’t thinking anything of the sort. Maybe he was just broken . . .
Messed up.
Incapable.
Bereft.
What did I know?
‘The differences in each of the four abnormalities are minuscule,’ Dr Reynolds continued. ‘In fact, they’re so minute – and so seemingly inconsequential – that they’re very easy to overlook. But once we began looking into them, it gradually became apparent that these almost imperceptible variations could be the answer to everything. We still don’t know exactly what they are, or how they function, but we’re reasonably confident now that these small variations create some kind of link between their parent abnormality and the gene variant that causes the relevant disorder. So in your nan’s case, the unknown mutation is linked to the variant that causes her blindness, and with Finch it’s linked to the abnormality responsible for his MD. We also think it’s possible that these links have something to do with the irregularities in the presentation of both disorders.’
‘What about my mum?’ I asked. ‘What’s this unknown abnormality linked to in her case?’
‘We don’t know yet. We’re still looking.’
‘And if you find it . . . will that tell us what killed her?’
‘If the coupling of her variants is consistent with the pattern in the other two genomes – and we’re fairly sure that it is – then the link should lead us to an abnormality that causes some kind of genetic disorder. Whether or not that turns out to be the direct cause of your mum’s death . . . well, we won’t know that until we find it. And even then, there’s no guarantee of an answer.’
From the way he looked at me then – his gaze direct and purposeful – I knew he was telling me something. And it wasn’t hard to guess what it was. Why he didn’t just come out and say it, I really don’t know. And as he sat there looking at me, clearly expecting me to take the initiative, I felt a flutter of resentment – and perhaps even anger – rising in my heart. But it only lasted a moment. I didn’t have the will or the energy to care about meaningless things.
‘The same goes for me, doesn’t it?’ I said to him. ‘Even if you find the link, there’s no guarantee that it’ll be the direct cause of my transparency. And even if it is, there’s no guarantee it’ll make any difference. Genetic disorders can’t be cured, can they?’
‘Well, there’s been some success with experimental gene therapy treatment, but you’re right – there’s no cure for the vast majority of genetic disorders. But that doesn’t mean there’s nothing to be done. In lots of cases it’s possible to treat and manage the symptoms of the disease . . .’
I don’t remember the rest of it. I think I’d reached a kind of saturation point, and my head was so full of abnormalities and variants and genes and disorders and DNA sequencing and god-knows-what else that I simply couldn’t take in any more, and something in my mind – some kind of safety mechanism – just shut everything down.
And I zoned out.
Just like Dad.
Only no one could see that I wasn’t there.
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