Pride and protein

Objective In Jane Austen's Pride and Prejudice, members of the Bennet family are either sensible or silly, and males are under‐represented. This study searches for an underlying medical diagnosis that explains these features. Design Very retrospective literature review. Participants Mrs Bennet, her five daughters (Jane, Elizabeth, Mary, Kitty and Lydia), her brother (Mr Gardiner) and her sister (Mrs Phillips). Main outcome measures Family tree and associated phenotypes Methods The author read Pride and Prejudice. A Bennet family tree was constructed. The number of male and female descendants was analysed using a binomial model. For each character, evidence of behaviour was collected, and members of the Bennet family were categorised as either sensible or silly. Results Males are under‐represented in Mrs Bennet's family. Assuming an equal probability of male or female offspring, this reaches statistical significance (binomial model, P  = 0.03). Approximately 50 % of females in the family are silly. Silly behaviour is more prevalent during social gatherings. Conclusions The family tree suggests an X‐linked genetic disorder, fatal in utero or in early life to affected males, explaining the paucity of male offspring. Female carriers survive, but with cognitive difficulties, explaining the approximate 50‐50 distribution of sensible and silly females in the family. The exacerbation of silliness during social gatherings may suggest an effect of protein intake, raising suspicions of a disorder of protein metabolism. Ornithine transcarbamylase deficiency is one such condition. Unfortunately, there remain significant challenges in performing genetic testing on fictional characters, so definitive evidence remains elusive. Jane and Elizabeth Bennet do not show signs of the disorder. However, carriers may be asymptomatic; they should be offered genetic counselling before Bingley or Darcy offspring are considered.