Fatahiyya

This group considers Abd Allah al-Aftah, the eldest son of the sixth Imam (Jaffar al-Sadiq), to have been the seventh Imam. There is little evidence of them surviving beyond al-Aftah’s death, since he is commonly believed to have left no descendents.[1]

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Reference
[1] Scripturalist Islam: The History and Doctrines of the Akhbārī Shiʿī School By Robert Gleave (Leiden: Brill, 2007), xxiii, 339 pp. EAN 978–9004157286. page 18