New Delhi: Prateek Yadav (38), younger son of Samajwadi Party founder Mulayam Singh Yadav, died in Lucknow on Wednesday morning. He was the son of Yadav and his second wife, Sadhna Gupta. His cremation will take place in Lucknow on Thursday.Family sources told ET that Prateek was found lying in the kitchen of his house early in the morning and was rushed to the Civil Hospital where he was declared brought dead. An autopsy was conducted and it described "cardiorespiratory collapse due to massive pulmonary thromboembolism" as the cause of death. Prateek was suffering from lung-related issues and was under medication.His wife, Aparna Bisht Yadav, had joined the BJP and is currently vice-chairperson of the Uttar Pradesh State Women Commission. Aparna, who was not in Lucknow, reached at her residence in the afternoon.SP president Akhilesh Yadav was the first one from the family to reach the King George Medical College, where the autopsy was conducted.