Spleen enlargement in the Bajau people is caused by a point mutation.

Caveats

• The term 'point mutation' has a specific scientific meaning (a single nucleotide change), and the most current peer-reviewed evidence (Nature, 2025) explicitly states this has not been confirmed as the causal mechanism for Bajau spleen enlargement.
• PDE10A genetic variants are associated with spleen size differences, but 'variants' is a broad term that encompasses regulatory changes, insertions, deletions, and other alterations — not just point mutations.
• Popular-science articles loosely use the word 'mutation' in ways that do not correspond to the precise technical term 'point mutation,' creating a misleading impression of scientific certainty.