They are off of the same lutino gene but produce a silver color...
The Platinum Cockatiels mutation is a sex-linked recessive gene that gives solid body-coloured birds in the same manner as Cinnamon. The usual differences between the sexes is still evident although there is often more yellow colouration present on the hens of this mutation than other solid coloured birds. The male does gain a melanin overlay as he matures making him generally a darker coloured bird than the hen. Usually the Platinum colour is deeper on the flight and tail feathers. Some Platinum birds almost appear a lavender shade when yellow pigments are present.
The Platinum gene is from the same family as the Lutino. A 'family' of genes is produced when more than one mutation is present at the same site on a chromosome. Here we have the lutino and platinum being at the same location yet having a different visual outcome. This has occurred as a result of a single gene being altered in two different ways giving us two genes that are both variations of the same original gene. I will discuss this further when we get to Platino Cockatiels.
The Lutino acts by preventing the depositing of the grey/brown family pigments or melanins. Platinum has the same effect but does not completely eliminate all the melanin as does Lutino. It is referred to as an 'intermediate' mutation. With Platinum Cockatiels some grey family pigments are still produced but in a lesser degree than the normal grey bird. They do contain melanin but it is a greatly reduced amount of pigment that is present. The resultant bird therefore has the appearance of half way between the normal grey with full compliment of melanin and the lutino which has no melanin. It can be easily differentiated from the other sex-linked gene, Cinnamon, by the fact that the cinnamon gene prevents brown pigments being converted to black and so has no grey pigments present and the Platinum gene allows the grey pigments to be produced but the amount deposited is much less. The amount of pigment produced in the cinnamon is not reduced at all as is the Platinum
lovely site that one is 
