My DD was a very early reader...picking out words at 17 months, 2nd grade level by 24 months, Rainbow Fairy books at 30 months. She loved books and would reenact the stories she read. She had great comprehension given her life experiences and age. She had a phenomenal memory which helped her learn to read by sight words. It seemed her mission in life was to read by 2. By 24 months she was typing short sentences on the computer.
Was she hyperlexic? No one ever assessed her, but in recent years she has been dx with Aspergers.
She does have a very high IQ (170 ex norms), so I now believe she is highly gifted with ASD, but also a highly precocious reader.

Academically, she is doing very well, her WIAT scores came at a time when school was failing her, but since then, she has taken off and is still 5 or so grades ahead of where she should be.