A somatic PIK3CA p.H1047L mutation in a Thai patient with isolated macrodactyly: a case report

Background: Macrodactyly is a rare congenital deformity characterized by gigantism of all structures of the digits. Previous reports showed that the mosaic PIK3CA variants were associated with overgrowth syndromes including macrodactyly. Objectives: To determine the genetic alteration in a Thai patient with enlarged soft tissue of the left middle and left fourth fingers with abnormal enlarged phalanges. Method: A nerve and a skin piece were separated from a therapeutically surgically removed part of the enlarged digit. Skin fibroblasts were cultured from the removed skin piece. DNA was isolated from the nerve tissue, cultured skin fibroblasts, and peripheral blood leukocytes. Polymerase chain reaction (PCR) followed by Sanger sequencing of PIK3CA was performed. Results: Mutation analysis revealed the c.3140A>T (p.(H1047L)) variant of PIK3CA in the nerve tissue and the cultured dermal fibroblasts but not in leukocytes from the peripheral blood. Conclusion: The somatic c.3140A>T (p.(H1047L)) variant of PIK3CA was found in a Thai patient with isolated macrodactyly, the same as those previously identified in other populations.