January 29, 1985

A dispatch on the Washington Talk page yesterday about furniture rentals carried an incorrect byline. The writer was Amy Wallace, not William N. Wallace.

AUTISM, a severe mental disorder that becomes evident in infancy, seems to have a genetic cause, according to a study of twins reported in the current issue of The American Journal of Psychiatry. The study was a rigorous one that sought out identical (one-egg) twins and fraternal (two-egg) twins in which at least one partner was suspected of having the disorder. In this way, the genetic contribution could be readily identified.

''Today, the 22d of January 1985, I am well and my friends Benjamin Weir and Jeremy Levin are also well.

Time Inc. and Newsweek have only lately discovered what some specialty publications have known for years: the value of the single-advertiser issue. Both publications have been experimenting with the one-sponsor, one-issue format, a staple of such magazines as Moviegoer and Veterinary Practice Management, which are published by the 1330 Corporation in Knoxville, Tenn. And both say they expect to go on using the device. ''Success tends to breed success,'' said Ken Noble, a Paine Webber Inc. analyst.

One of five Americans apparently kidnapped in Beirut over the last 10 months was seen today in a 56-second videotape in which he called on the United States to ''take action for our release quickly.'' However, the American, William Buckley, a political officer in the United States Embassy in Beirut, did not specify what Washington had to do to gain freedom for the five. On the videotape, Mr. Buckley said that he and two other missing Americans were well. He mentioned Jeremy Levin, the Beirut bureau chief for the Cable News Network, and the Rev. Benjamin M. Weir, a Presbyterian minister.