Mrs Danczuk, 31, married to Rochdale's Labour MP Simon Danczuk, alleges she was raped and sexually assaulted "hundreds of times" at her family home in Middleton, Greater Manchester. A 36-year-old man was arrested last week on suspicion of rape and later bailed pending further inquiries.
Today, the Daily Mail disclosed that the suspect is her brother, Michael Burke.
He told the newspaper: " I feel very angry about the whole situation. My whole life has been turned upside down and I fear leaving the house because people might attack me. The allegations are false.
"This is just another part of the media circus that she has created around herself."
The siblings' father, Martin Burke, also told the newspaper this was "one time" he could not support his daughter.
Mrs Danczuk, who became well known for her Twitter selfies featuring her cleavage, claims the abuse took place between 1989 and 1995 when she was aged between six and 12.
She waived her right to anonymity in a front page interview with The Sun and later told the Mail on Sunday that she had reported her alleged attacker to police.
Her husband has been been campaigning on the issue of child sex abuse in the wake of the 2012 grooming scandal in Rochdale.
In an apparent response to today's Daily Mail article, Mrs Danczuk tweeted: "Sticks and stones may break my bones but words will never hurt me."
A spokesman for Greater Manchester Police said the investigation was progressing and detectives were aiming to arrange a video interview with Mrs Danczuk.