PROP1 and obesity due to melanocortin 4 receptor deficiency: Furthermore, research on untreated individuals with deletions in the GH gene, those experiencing multiple pituitary hormone deficiencies caused by PROP-1 gene mutations, and individuals with isolated IGF-I deficiency due to deletions or mutations in the GH receptor gene, despite displaying signs of premature ageing like skin wrinkles, obesity, insulin resistance, and osteopenia, indicates the emergence of a longer life expectancy, with some reaching ages between 80 and 90 years [37].