Mental Retardation, AD 53

Background and History: 

This is one of a large number of mental retardation disorders in which a gene change (mutation) is responsible.  The mutation leads to widespread neurological dysfunction.

Clinical Correlations: 

Poor muscle tone is evident early leading to the 'floppy baby' designation.  Developmental milestones are delayed and many children never learn to walk or speak.  Intellectual disabilities range from mild to severe.  Seizures occur in many infants and children.  Breathing problems, feeding difficulties and slow physical growth are frequently present.  Behavioral features including anxiety, hyperactivity, aggression, and signs of autism have been reported. 

The lid openings slant downward and the upper lids have a prominent extra fold (epicanthal fold).  Visual impairment with poor visual tracking may be present.

The MRI scan of the brain may be normal.


A gene change (mutation) has been identified in this condition.  The neurologic impairment prevents reproduction but the nature of the mutation suggests that an autosomal dominant inheritance pattern would be expected.

Diagnosis and Prognosis: 

There are no physical or neurologic signs specific to this disorder and a gene study is necessary to the diagnosis.  Pediatricians and neurologists are likely to collaborate in the evaluation and care of these patients.  No treatment has been reported and nothing is known regarding longevity.

An EEG (electroencephalogram) and a brain MRI may be used but the findings are not specific to this condition.

Additional Information
Autosomal dominant