And individuals who have classic galactosemia basically have an inability to actually digest the galactose molecule. So these individuals can actually break down that lactose into, these two individual monosaccharides and the cells can then uptake these two sugars. But then those individuals with classic galactic cannot actually break down this galactose molecule. And the build up of the galactose can lead to many different problems as we'll see in just a moment. Now, classic galactosemia is an autosomal recessive disease. And what that means is, so let's suppose we have some chromosomal pairs, that individual, what that basically means is these are two genes, two alleles for the same type of enzyme, for some specific type of enzyme.