John F. Kennedy Jr., a scion of the nation's most celebrated political dynasty, was reported lost and presumed dead in an accident that resounded this weekend with echoes of the family's many misfortunes.

Mr. Kennedy, 38, has been missing since Friday night after the plane he was flying to a cousin's wedding on Cape Cod failed to arrive on Martha's Vineyard. His disappearance in the prime of his life, like the deaths of his father, two uncles, an aunt and two cousins before him, only added to the perception that his larger-than-life family has been besieged by a near-biblical blight.

Mr. Kennedy, son of the 35th President, was touched by both the Kennedy charisma and its curse. The public ached in 1963 as it watched him, in his blue dress coat and short pants, salute his slain father. It cheered as he emerged with his dazzling bride from their secret wedding in 1996. And as he sought a measure of privacy even while forsaking a career in law or government for a role in publishing, the public never ceased dwelling on his future and the swings of his family's fortunes between triumph and disaster.

Guiding his life was a scriptural passage, Luke 12:48, that was voiced frequently by his grandmother Rose and paraphrased by his father: ''Of those to whom much is given, much is required.'' Mr. Kennedy taught English to underprivileged children, aided people who were homeless and disabled, and was a patron of the arts.