My DS (also 16 months) does not have a diagnosis (we are seeing SALTs and developmental paediatricians and have an appointment with an autism expert, Daphne Keen, in June.
The things that we are concerned about are:
- not brilliant eye contact;
- inconsistent responding to his name;
- doesn't point;
- no shared interest - e.g. he won't bring us toys to show us or look at us much while we are playing together with toys;
- no speech (although he babbles a lot);
- very independent and happy to be on his own; and
- likes spinning things and open/shutting doors.
It's very hard when you first start to wonder, I know. I would make a list of all your concerns (diaries are a good idea) and see your GP or HV - they should refer you to SALT and a developmental paediatrician. It can take months to actually get an appointment so I would start now - you can always cancel nearer the time if you start to see improvement. Also, in the meantime, perhaps try reading into how you can try to improve engagement with you (e.g. the Hanen books, Greenspan's Floortime, etc.). I must say we have seen a definite improvement since we really started trying to engage with him (he was always so happy playing on his own I must admist we probably didn't do enough of it before!). The absolute key is - if there is a problem, the earlier you can get it diagnosed and start on therapies, the more effective they are likely to be.
I would also say that when I posted something similar a couple of months back a good few people very kindly posted to say their child was exactly the same at that age but it turned out to be nothing at all and they are absolutely fine! So try not to worry too much - it's great that you are so on the ball to be able to spot potential signs but please also be aware that 16 months is very young (MCHAT is designed for babies 18 months plus) and he may just be a little behind.
Good luck and feel free to PM me! I got terribly anxious about it all at the time (am fine now!) and it helps to talk.