Inhibition of autism spectrum disorder using decoy antigens to maternal brain-reactive antibodies

1. A method of inhibiting or reducing development of an autism spectrum disorder in a fetus or an infant comprising administering to a mother pregnant with the fetus or prior to the fetus being born as an infant while the mother is pregnant, an amount of an agent comprising a peptide comprising the sequence of an extracellular portion of a contactin-associated protein 2 (Caspr2) effective to inhibit or reduce development of an autism spectrum disorder in a fetus or an infant.

2. The method of claim 1 , wherein the Caspr2 is human.

3. The method of claim 1 , wherein the agent comprises a fusion protein which comprises a peptide comprising the sequence of an extracellular portion of a Caspr2.

4. The method of claim 1 , wherein the mother has been diagnosed as at risk for an autism spectrum disorder in her fetus by a method comprising obtaining a sample from the mother's blood and quantifying the level of antibody directed to Caspr2 in the sample, and comparing the level so quantified to a predefined control level of the respective antibody, wherein an antibody level in the sample in excess of the control level has been determined, so diagnosing the mother as at risk for an autism spectrum disorder in her fetus.

5. The method of claim 1 , further comprising an initial step of receiving identification of the mother as being at risk for an autism spectrum disorder in a fetus she is pregnant with and administering the amount of an agent to the mother so identified.

6. The method of claim 1 , wherein the method is of inhibiting or reducing development of an autism spectrum disorder in a fetus and wherein the amount of agent is administered to a mother pregnant with the fetus.

7. The method of claim 1 , wherein the method is of inhibiting or reducing development of an autism spectrum disorder in an infant comprising administering to a mother pregnant prior to the fetus being born as an infant while the mother is pregnant.

8. The method of claim 1 , wherein the fetus or infant is male.

9. A method of inhibiting or reducing development of an autism spectrum disorder in a fetus or an infant comprising extracorporeally contacting blood of a mother (i) pregnant with the fetus or (ii) prior to the fetus being born as an infant while the mother is pregnant, with an amount of an agent comprising a peptide comprising the sequence of an extracellular portion of a contactin-associated protein 2 (Caspr2) so as to reduce the blood levels of an antibody directed to Caspr2, and recirculating the blood so treated back into the mother effective to inhibit or reduce development of an autism spectrum disorder in a fetus or an infant.

10. The method of claim 9 , wherein the fetus or infant is male.