When medical diagnoses are difficult to achieve based on clinical information alone, a patient experiences a diagnostic odyssey and undergoes multiple clinical evaluations, imaging studies, and laboratory tests. The challenges brought on by the odyssey result in delayed or inaccurate clinical management. Shortening or ending the odyssey could have significant clinical, psychosocial, and economic benefits.1 Symptoms that may lead to diagnostic odysseys include seizures, respiratory failure, cardiac failure, hypotonia, hypoglycemia, and jaundice. Individuals with rare diseases are most often younger than 5 years and undergo lengthy diagnostic odysseys; 80% of rare diseases are associated with genetic variants.