PCSK1 and Bardet-Biedl syndrome: NCT04966741: A study to evaluate the efficacy, safety and tolerability of setmelanotide over 1 year of treatment, in pediatric patients aged 2 to <6 years with obesity due to either biallelic variants of the POMC, PCSK1 or LEPR genes or Bardet‐Biedl Syndrome (BBS)