Mental Retardation, AD 57

Background and History: 

Several families have recently been reported with this condition in which psychomotor delays and intellectual disabilities are associated with facial anomalies and variable skeletal malformations.

Clinical Correlations: 

Newborns and infants often have feeding problems.  Many patients later complain of diarrhea or constipation.  Physical growth delays resulting in short stature may occur.  Most individual exhibit developmental delays and have some degree of intellectual disability.  The spine may have an abnormal curvature (scoliosis), while contractures in the hands and skull anomalies, and a highly arched palate have been reported in some patients.  The joints are often hypermobile.  Behavior problems such as anxiety and hyperactivity are common while features of autism spectrum disorder are often reported

Psychomotor delays and intellectual disabilities are usually present.

Various facial and external eye anomalies are common.  The eyelids often droop and may have an extra fold of skin known as epicanthal folds, the lid openings often slant upwards, and the eyes appear abnormally far apart.  Refractive errors requiring eyeglasses, especially nearsightedness, are common.


A single dose of a mutation in the TLK2 gene is responsible for this disorder.  The pattern of transmission is vertical as is characteristic for an autosomal dominant mode of inheritance.  Affected individuals rarely reproduce however.

Diagnosis and Prognosis: 

The physical characteristics at birth are generally nondiagnostic and do not suggest a specific condition.  Neurologists, pediatricians, orthopedists and geneticists are likely to collaborate in the diagnosis and care of patients with this disorder.  Gene studies may be necessary for specific diagnosis.

No treatment has been reported and nothing is known regarding longevity.

Additional Information
Autosomal dominant