Floppy Infant

Reference work entry

A floppy infant is an infant with poor muscle tone affecting the limbs, trunk, and the craniofacial musculature. The causes are numerous (heterogeneous etiologies) and the workup in many instances can be complex. The task of evaluating infants with hypotonia is difficult and complex.

Synonyms and Related Disorders

Congenital hypotonia

Genetics/Basic Defects

  1. 1.
    Heterogeneous causes of hypotonia (Prasad and Prasad 2003; Igarash 2004)
    1. a.
      Chromosome disorders: central hypotonia
      1. i.

        Aneuploidy: e.g., Down syndrome (one of the most frequently encountered cause of neonatal hypotonia)

      2. ii.

        Microdeletions: e.g., Prader–Willi syndrome (neonatal hypotonia, feeding problems, and failure to thrive with later onset of hyperphagia and obesity)

      3. iii.

        Subtelomeric cryptic deletions (relatively new category of disorders that account for unexplained mental retardation): e.g., terminal 22q13.3 deletion syndrome (neonatal hypotonia can be a prominent feature)

    2. b.
      CNS malformations/encephalopathies...


Spinal Muscular Atrophy Survival Motor Neuron Congenital Muscular Dystrophy Congenital Myopathy Very Long Chain Fatty Acid 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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