Oneliner_1277

OneLiner

Germline mosaicism is a mutation in the egg or sperm cells, where half of the gametes carry the mutation and the other half do not. Germline mutations will not present phenotypically in the carrier of the gametes but instead will be passed on and expressed in their offspring. Therefore, the patient presents with symptoms of the disorder but the parents do not. Eg: 3-year-old patient is diagnosed with a right midshaft humeral fracture after a minor fall. This is one of many fractures that he has had since birth and he also has blue sclerae. Neither parent has ever sustained a fracture, but an older son had similar symptoms when he was younger. This depicts a classic presentation of osteogenesis imperfecta in both children due to germline mosaicism.