Microphthalmia, Syndromic 1

Background and History: 

The eye may be abnormally small (microphthalmia) both as an isolated anomaly or as part of a more extensive syndrome as in this disorder.  Often other ocular malformations are present as well. 

Clinical Correlations: 

The small eyes are accompanied by small corneas (windshield of the eye) and defects in formation known as colobomas.  One or both eyes may be involved.  Various skeletal abnormalities such as short stature, ‘caved-in chest” (pectus excavatum), small skull (microcephaly), absence of the clavicle bones, spinal deformities, a highly arched palate, and duplicated thumbs and misshaped digits are usually present. The digits may be curved and sometimes have webbing between them.  In addition there are anomalies of the genitalia (males) such as a small penis, an abnormal urethral opening, and small testicles.  Some teeth may be missing and the incisors are often malformed and have wide spaces between them.  The kidneys can be abnormal as well.  More than half (63%) have a degree of intellectual deficit.  The ears can be abnormally shaped and may be low-set and rotated posteriorly. 


This is an X-linked recessive disorder secondary to an unidentified mutation on the X chromosome.  Males (with a single X chromosome) are affected but their malformations usually prevent reproduction.  No abnormalities are seen in carrier females whose second normal X chromosome apparently covers for the mutation on the other X chromosome. 

Diagnosis and Prognosis: 

The diagnosis is usually made by pediatricians in collaboration with medical geneticists and ophthalmologists.  No treatment is available for this syndrome beyond symptomatic and supportive therapy for specific health issues.  Blindness is not uncommon. 

Additional Information
X-linked recessive, carrier mother
X-linked recessive, father affected