Understand the Conditions
Other rare genetic conditions
that cause obesity
Steroid receptor coactivator-1 deficiency, also known as SRC1 deficiency, and SH2B adaptor protein 1 deficiency, also known as SH2B1 deficiency, are two rare genetic diseases.
Symptoms of SRC1 deficiency
People living with SRC1 deficiency have specific gene changes, or variants, in one of their genes (called the NCOA1 gene) that keep the brain from understanding that the body is full. SRC1 deficiency can be passed on to a child by a single parent who has a change in the NCOA1 gene.
Key signs and symptoms of SRC1 deficiency include:
- Constant, hard-to-control hunger (known as hyperphagia)
- Severe, early-onset obesity
- High levels of leptin (a hormone)
- High levels of insulin
Symptoms of SH2B1 deficiency
People living with SH2B1 deficiency have specific gene changes, or variants, in one of their genes (called the SH2B1 gene) that keep the brain from understanding that the body is full. SH2B1 deficiency can be passed on to a child by a single parent who has a change in the SH2B1 gene.
Key signs and symptoms of SH2B1 deficiency include:
- Constant, hard-to-control hunger (known as hyperphagia)
- Severe, early-onset obesity
- High levels of leptin (a hormone)
- High levels of insulin
- Short stature
How SRC1 and SH2B1 deficiencies are inherited
SRC1 and SH2B1 deficiencies are inherited in an autosomal dominant manner. This means that you need only one copy of the genetic variant to develop the condition. You inherit an autosomal dominant disorder from a parent who also has a single copy of the genetic variant.
SH2B1 deficiency can also be caused when a part of the DNA that includes the SH2B1 gene is missing. This type of genetic deletion can occur spontaneously and is not always inherited.