Hypotonia, Infantile, with Psychomotor Retardation And Characteristic Facies 1

Clinical Characteristics
Ocular Features: 

Nystagmus, strabismus and sometimes optic atrophy have been noted.  Poor fixation may be present.   

Systemic Features: 

This progressive disorder can be evident at birth based on the facial dysmorphism.  The face is triangular, the forehead is prominent, the nose is small, the ears appear large and low-set.  The mouth appears wide with a thin upper lip.  Early development may be near normal for the first 6 months but thereafter psychomotor regression and slow physical growth are evident.  Patients have microcephaly and seldom achieve normal milestones.  Spasticity in the extremities and truncal hypotonia with distal muscle atrophy are evident.  The face appears triangular, the forehead is prominent, the nose is small, and the ears appear large and low-set.  Pectus carinatum and pes varus may be present.   Males often have cryptorchidism.

Brain imaging has revealed cerebellar atrophy and "while matter abnormalities".  Sural nerve biopsies show evidence of infantile neuroaxonal dystrophy.

Some individuals are less severely affected, retain the ability to speak, and are able to walk at least into the second decade of life.


Based on transmission patterns this condition is inherited as an autosomal recessive disorder caused by mutations in in the NALCN gene (13q32.3-q33.1.

For somewhat similar disorders caused by mutations in other genes see IHPRF2 (616801) and IHPRF3 (616900).

Autosomal recessive
Treatment Options: 

No treatment has been reported.

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