Possible genetic defect in parakeet babies?

Hi, if you remember me; you remember that my 7 month old parakeet had to be taken to the avian emergency care clinic about a month ago. She unfortunately didn't make it ='( but now the question is on the rise about a possible genetic defect that might have occurred in the baby keet's DNA. We spent hours waiting for any possible information leading to her severe condition and the best that the doctor could figure was that it was a neurological problem that would've spontaneously appeared in her DNA line. If that is true, is it possible that any of the other 'baby' keet's-- her brother and sisters-- might develop this same neurological condition that can kill them? I now own the mother and father keet's, and six wonderful babies... I would be heart broken if this happened to any of my other babies. I really would appreciate it if you know anything about bird genetics and the possibility of this spontaneously appearing again in one of my other budgies. Thank you so much for your time; God bless. =)