Former high-ranking Russian official Anatoly Chubais is being treated in a European hospital with symptoms of Guillain-Barre syndrome, a neurological condition, according to prominent Russian journalist and TV personality Ksenia Sobchak. Sobchak says she spoke with Chubais’ wife, who said that “her husband’s condition is unstable. He felt bad very suddenly, he started to stop feeling his arms and legs.” Sobchak is the daughter of the late Anatoly Sobchak, the former mayor of St. Petersburg and political mentor to Russian President Vladimir Putin. She was also a candidate for the presidency of Russia in 2018. In recent years she has been critical of Putin, including Russia’s invasion of Ukraine. Sobchak also directly mentioned Chubais, saying about his condition: “I was hospitalized in one of the European clinics with a diagnosis of Guillain-Barr syndrome. Moderate condition, stable.’ According to the US Centers for Disease Control and Prevention, Guillain-Barre syndrome is a rare disorder in which the immune system damages the body’s nerves. Chubais did not respond to a request for comment from CNN and it is unclear where he is currently in Europe. Kremlin spokesman Dmitry Peskov said Monday that the Kremlin does not have details about what happened to Chubais, but called the development “sad news.” Some background: Chubais resigned as the Kremlin’s special envoy for the environment in March. Reuters, citing two sources familiar with the matter, said he left the country because of the war in Ukraine. Chubais did not respond to CNN’s request for comment at the time. In March, the Kremlin confirmed that Chubais had left his job. Chubais had been working in the environmental sector since December 4, 2020, TASS reported. He rose to prominence as Boris Yeltsin’s finance minister in the 1990s. In the early days of Putin’s rise to power, Chubais was seen as a rival by the current President. Putin claimed in a series of interviews in 1999 that Chubais rescinded the Kremlin job he was originally offered. In recent years, Chubais continued to call for economic reform and was one of the few remaining liberals associated with the Russian government.