Overview

• New England Journal of Medicine follow-up shows all eight UK-born children developing normally through two years, with isolated cases of treatable heart, metabolic and neurological conditions.
• Newcastle Fertility Centre has performed 22 mitochondrial replacement treatments since 2023, resulting in eight live births and one ongoing pregnancy.
• Residual heteroplasmy was detected in three infants at rates up to 16 percent, underlining the need for technical refinements to reduce mutated mitochondria further.
• The technique lowers the risk of mitochondrial disease from about 1 in 50 to roughly 1 in 130 without fully eliminating the possibility of inherited defects.
• The UK’s HFEA authorizes each mitochondrial replacement case individually, with Germany maintaining a ban under its Embryonenschutzgesetz.