Growth Hormone Defects
Growth Hormone Defects
Growth Hormone Deficiency
Growth hormone deficiency results in reduced levels of growth hormone and, consequently, reduced levels of IGF-1.
In most cases, isolated growth hormone deficiency is due to defects in the GH1 gene, which is responsible for growth hormone production.
However, we need to rule out general hypopituitarism, in which other anterior pituitary hormones are also low.
Treatment: Recombinant human growth hormone.
Growth Hormone Insensitivity
Growth hormone insensitivity is characterized by normal or high levels of growth hormone, and low levels of IGF-1.
Insensitivity is caused by growth hormone receptor defects, which may be hereditary, as in Laron Syndrome, or acquired as a result of malnutrition, liver disease, diabetes, growth hormone receptor antibodies, or other pathologies.
Treatment: recombinant IGF-1.
Effects of Growth Hormone Defects:
In Childhood:
- If the defect appears in childhood, linear growth is slow (sometimes called pituitary dwarfism);
- These patients often have delayed puberty, with small gonads and genitalia (micropenis).
- If growth hormone defects appear later in life, adults present with body composition changes, including reduced muscle and bone mass, and increased fat mass.
- These patients have increased risk of cardiovascular disease (including left ventricular dysfunction and hypertension), and are more likely to develop insulin resistance.
- Additionally, be aware that reduced exercise capacity, lethargy, and depression may contribute to a lower quality of life in these patients.
For full references, please see our tutorial on Growth Hormone Pathologies