SC4MOL deficiency

Microcephaly, Congenital Cataracts, and Psoriasiform Dermatitis

Clinical Characteristics
Ocular Features: 

Congenital cataracts are usually present.  No further description is available.  Some individuals have a chronic blepharitis.

Systemic Features: 

Small stature, microcephaly, and developmental delay are important features. The skin in early life, even in infancy, may have an psoriasiform dermatitis that waxes and wanes in some patients while others have only dry skin.  Chronic arthralgias are sometimes present leading to joint contractures especially in the lower extremities.  Skeletal maturation is delayed and there may be cognitive deficits.

Serum total cholesterol levels are generally low but triglycerides are in the normal range.  Serum levels of IgE and IgA may be elevated.  This condition results from defects in the cholesterol synthesis pathway.


Compound heterozygosity or homozygosity of mutations in the SC4MOL gene (4q32.3) (also known as MSMO1) is responsible for this condition.  Parents with a single mutation may have mildly elevated plasma methylsterol levels.

Autosomal recessive
Treatment Options: 

Cholesterol supplementation and the use of statins has been reported to improve symptoms.  The usual treatments for psoriasis may provide some temporary relief.  Physical therapy may prevent joint contractures.  Antibiotic drops or ointment may be helpful in the treatment of blepharitis.

Article Title: 

The role of sterol-C4-methyl oxidase

He M, Smith LD, Chang R, Li X, Vockley J. The role of sterol-C4-methyl oxidase
in epidermal biology
. Biochim Biophys Acta. 2014 Mar;1841(3):331-5. Review.

PubMed ID: 
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