Hypotonia, Infantile, with Psychomotor Retardation And Characteristic Facies 1

Background and History: 

Hereditary neurological conditions occur in many forms but few are as severe as this one.  Both physical and neurological development are important features.

Clinical Correlations: 

The skull is small (microcephaly), the forehead is prominent, the face appears triangular, the ears are large and low-set, the mouth is large (with a thin upper lip, and babies are floppy (hypotonic).  This enables one to make a tentative diagnosis in the new born period.  Development may be near normal in the first months of life but certainly after 6 months of age it is evident that physical growth and neurological development are subnormal.  Many infants never achieve normal developmental milestones such as sitting, walking, and talking.  Eventually wasting of muscles becomes evident.  Others may not be so severely affected and may retain the ability to walk into the second decade of life.

Most infants are not able to visually fixate on targets and the eyes have to-and-fro movements (nystagmus) and may be misaligned (strabismus).  Pale optic nerves (optic atrophy) have been reported indicating that they are unable to properly carry visual signals from the eye to the brain.

Brain imaging and studies of nerve biopsies may show underdevelopment of the brain and nerve cells.


This condition is transmitted in an autosomal recessive pattern requiring the presence of mutations in both members of a specific pair of genes.  Parents are clinically normal but carry one mutated copy.  The risk to each child of two such parents has a 25% risk of this condition.

Diagnosis and Prognosis: 

Neurologists and pediatricians are likely to collaborate on the diagnosis of this condition.  There is no treatment and little is known about longevity although those individuals more mildly affected may live to adulthood.  Brain imaging with nerve studies and DNA analyses may be necessary to confirm the diagnosis.

Additional Information
Autosomal recessive