Severe disfigurement and premature death occur in case of

Acromegaly is a rare hormonal disorder caused by the excessive production of growth hormone (GH) after the growth plates of the bones have closed (in adulthood). 

The main characteristic of acromegaly is the enlargement of certain body parts, particularly the hands, feet, and facial features. This occurs due to the overgrowth of bones and tissues in response to the excess GH. Other symptoms can include joint pain, thickened skin, enlarged organs, and changes in facial appearance.