Some varieties of "autism" may be related to neuroligins

This is quite preliminary, but it smells like something worth tracking. Note that some neuroligin mutations have also been associated with schizophrenia.

BBC NEWS | Health | Protein mutations link to autism

Scientists have discovered how mutations in two key proteins may lead to autism.

They have shown one protein increases the excitability of nerve cells, while the other inhibits cell activity.

The University of Texas team found that in normal circumstances the proteins balance each other out.

But the study, published in Neuron, suggests that in people with autism the balance between the proteins is knocked out of kilter.

The findings back the theory that autism involves an imbalance between excitatory and inhibitory connections between nerve cells...

...The proteins - neuroligin-1 and neuroligin-2 - create a physical bridge at the junction - or synapse - of nerve cells, enabling them to make connections with others...

...Neuroligin-1 was associated with excitatory connections and neuroligin-2 with inhibitory connections.

When they introduced a mutant form of neuroligin-1 thought to be carried by some people with autism the number of synapses fell dramatically - and the cells became significantly less excitable...

... carrying a mutant form of neuroligin-1 may depress the number of synapses that make it into adulthood....

The neuroligins are very likely to tell an interesting story ...