Hypotonia is a condition characterized by severely reduced muscle tone. It is seen primarily in children. When hypotonia affects adults, it may be due to cerebellar degeneration. Hypotonia is not the same as muscle weakness but it can co-exist with muscle weakness. It does not affect intellect. However, depending on the underlying condition, some children may take longer to develop social, language, and reasoning skills.

Hypotonia is also called Floppy, Decreased muscle tone, and Hypotonic infant.


The most common symptoms of hypotonia involve problems with mobility and posture, breathing and speech difficulties, lethargy, ligament and joint laxity, and poor reflexes.


Hypotonia may be caused by trauma, environmental factors, or by genetic, muscle, or central nervous system disorders.

In some cases, the cause is not apparent. Sometimes it may not be possible to find the cause of the hypotonia. While most children tend to flex their elbows and knees when resting, hypotonic children hang their arms and legs by their sides. They also may have substantial weakness and little or no head control, giving them a “floppy” appearance.

Some common conditions that cause hypotonia are:

  • Down syndrome
  • Infant botulism
  • Myasthenia gravis
  • Cerebellar ataxia, congenital
  • Prader-Willi syndrome
  • Myotonic dystrophy
  • Kernicterus
  • Riley-Day syndrome
  • Marfan’s syndrome
  • Hypervitaminosis D
  • Muscular dystrophy
  • Achondroplasia
  • Trisomy 13
  • Sepsis
  • Aicardi syndrome
  • Canavan disease
  • Congenital hypothyroidism
  • Krabbe disease
  • Menkes syndrome
  • Metachromatic leukodystrophy
  • Methylmalonic acidemia
  • Rickets
  • Spinal muscular atrophy type 1 (Werdnig- Hoffman)
  • Tay-Sachs disease

Treatment options

Treatment options depend on the cause. When hypotonia is caused by an underlying condition, that condition is treated first, followed by symptomatic and supportive therapy.

Physical therapy is often used to improve fine motor control and overall body strength. Occupational and speech-language therapy is beneficial in decreasing breathing, speech, and swallowing difficulties. Therapy for infants and young children may also include sensory stimulation programs.