The purpose of this study is to determine if there are genetic variations that can explain a genetic basis for cyclic vomiting syndrome (CVS).

The purpose of this study is to determine if there are genetic variations that can explain a genetic basis for cyclic vomiting syndrome (CVS), various phenotypes of CVS (e.g. menstrual, Sato, calendar-tied) and migraine headaches (e.g. with aura, without aura, hemiplegic migraine). This information will allow physicians to improve care for patients who have been diagnosed with this disease and to provide their parents with more complete information regarding the cause of this disease. This research is being done because many unanswered questions remain regarding children with CVS.

Inclusion Criteria:

• Subjects age 0-21 years old with CVS (different phenotypes). Each patient's authorized legal guardian must understand the nature of the study and must provide written informed consent.

Exclusion Criteria:

• Subjects age > 22 years old Vomiting is not due to CVS or other related condition

Cyclic vomiting syndrome (CVS) may be the most severe recurrent vomiting disorder in humans. CVS is characterized by a sudden onset of rapid-fire vomiting, usually beginning in the early morning hours or upon wakening. It has a peak vomiting intensity of every 5-10 minutes (6-12 emeses) and episodes last between 2 hours and 10 days. These episodes of acute vomiting occur on average once every 2 to 4 weeks. The child returns to completely normal health between vomiting episodes. Children are diagnosed based on their specific vomiting pattern and a lack of positive findings on laboratory testing.