Medical Syndromes: Definition, Classification, and Common Examples

What Is a Syndrome?

A syndrome (Greek syndromē, "running together") is a constellation of signs and symptoms that consistently occur together and characterize a specific disease, disorder, or condition.

Classification

• By etiology: Genetic (Down, Turner, Klinefelter), environmental (fetal alcohol), infectious (AIDS), autoimmune (Sjögren's).
• By domain: Physical (Marfan), psychological (depressive syndrome), behavioral (Tourette), mixed.
• By system: Cardiometabolic (metabolic syndrome), neurological (Guillain-Barré), dermatologic (Steven-Johnson).

Diagnosis

Clinical criteria (major/minor features), supported by labs, imaging, genetics. No single test for most syndromes.

Management

• Treat underlying cause if identifiable.
• Symptom-based multidisciplinary care.
• Genetic counseling for heritable syndromes.
• Surveillance for associated complications (e.g., cardiac in Marfan, leukemia in Down).

Notable Examples

Syndrome	Key Features
Down syndrome	Trisomy 21; intellectual disability, characteristic facies, cardiac defects
Turner syndrome	45,X; short stature, ovarian dysgenesis, coarctation
Klinefelter syndrome	47,XXY; hypogonadism, tall stature, infertility
Marfan syndrome	FBN1 mutation; aortic root dilation, lens dislocation, arachnodactyly
Cushing's syndrome	Cortisol excess; central obesity, hypertension, glucose intolerance
Metabolic syndrome	Central obesity, dyslipidemia, hypertension, insulin resistance
Sjögren's syndrome	Autoimmune exocrinopathy; dry eyes/mouth, fatigue, lymphoma risk