Rapid-onset obesity is a large weight gain in a short amount of time (15 to 20 lbs in a 6- to 12-month period with onset between 1.5 and 10 years of age.)

Hypothalamic dysfunction is when the hypothalamus does not function properly.

Some symptoms include:

• Increased weight gain in short amount of time
• Hypothyroidism (causing fatigue, weight gain, hair and skin changes, cold intolerance)
• Growth hormone insufficiency
• Diabetes insipidus
• Syndrome of inappropriate antidiuretic hormone (SIADH)
• Excessive or diminished thirst due to water/salt imbalance

Hypoventilation is breathing that is not adequate to meet the needs of the body, or reduced lung function.

Autonomic dysregulation is the impairment of the autonomic nervous system.

Some symptoms include:

• Altered sweating
• Decreased body temperature
• Decreased sensitivity to pain
• Cold extremities — hands and feet
• Bradycardia — decrease in heart rate
• Chronic diarrhea or constipation

ROHHAD is a very rare disorder with only more than 75 cases identified by our laboratory thus far.