A mother has been jailed for up to 30 years after burning her 19-year-old son's penis and nipples with a lighter.

Christine Gelineau from Massachusetts pleaded guilty to first-degree assault and witness tampering, after she also coerced her son to lie about the abuse.

At a hearing in New Hampshire the youngster described in detail the brutal abuse she subjected him to.

"Dear ex-Mother," he began as he read from a prepared statement. "What you did to me is unforgivable.

"You beat me, starved me, almost chopped my penis off, threw my clothes away, wouldn't let me bathe.

"You almost killed me by having me take three (antidepressants) and two muscle-relaxers.

He continued: "Now that I know you're a complete criminal and only wanted me dead so you could go back to your old life.

"You won't be able to attend my graduation or see me go on to college, so I wish you goodbye. I hope you realize you have lost everything you had."

In the affidavit for the case Gelineau admitted to burning the tip of her son's penis, but claims she only did so after he threatened to have sex with her.

She then put on gloves and grabbed and twisted his penis before holding a lighter to it for several seconds.

The injuries suffered, which were later confirmed to be second and third degree burns, have left him with permanent nerve damage.