OPHN1 syndrome

Alternate names

Oligophrenin-1 syndrome; OPHN1- related XLID; OPHN1 XLMR, X-linked intellectual disability; OPHN1 XLMR; OPHN1 Deficiency; X-linked intellectual disability-cerebellar hypoplasia syndrome; Intellectual disability, X-linked, with cerebellar hypoplasia and distinctive facial appearance; X-linked Intellectual Deficit with Cerebellar Hypoplasia

Definition

OPHN1 syndrome is a rare disorder characterized by intellectual disability and changes in the part of the brain which controls movement and balance (cerebellum). The syndrome mainly affects males.

Cause

• OPHN1 syndrome is caused by mutations in the OPHN1 gene, which is located on the X chromosome.
• Some females who carry a mutation in the OPHN1 gene may have mild learning disabilities, mild cognitive impairment, strabismus, and subtle facial changes.

Inheritance

This condition is inherited by X-linked manner.

Signs and symptoms

Signs and symptoms may include intellectual disability, low muscle tone (hypotonia), developmental and cognitive delay, early-onset seizures, abnormal behavior, small or underdeveloped genitals, characteristic facial features (long face, bulging forehead, under eye creases, deep set eyes, and large ears), crossed eyes (strabismus) and inability to coordinate movements.

Clinical presentation

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed.

80%-99% of people have these symptoms

• Cerebellar hypoplasia(Small cerebellum)
• Global developmental delay

30%-79% of people have these symptoms

• Abnormal facial shape(Unusual facial appearance)
• Ataxia
• Deeply set eye(Deep set eye)
• Focal impaired awareness seizure
• Generalized [[hypotonia](Decreased muscle tone)
• Generalized myoclonic seizure
• Intellectual disability, moderate(IQ between 34 and 49)
• Intellectual disability, severe(Early and severe mental retardation)
• Partial absence of cerebellar vermis
• Poor eye contact
• Poor speech
• Strabismus(Cross-eyed)
• Tall chin(Increased height of chin)
• Ventriculomegaly

5%-29% of people have these symptoms

• Attention deficit hyperactivity disorder(Attention deficit)
• Caudate atrophy
• Enlarged cisterna magna
• Frontal cortical atrophy
• Intention tremor
• Mandibular prognathia(Big lower jaw)
• Postural instability(Balance impairment)
• Prominent nose(Big nose)
• Retrocerebellar cyst
• Temporal cortical atrophy
• Wide nasal bridge(Broad nasal bridge)

Diagnosis

• Medical imaging reveals changes in the cerebellum with hypoplasia, dysgenesis and cleft formation in the posterior parts of the cerebellar worm, as well as atrophy of the cortex with enlarged cerebral ventricles .
• The diagnosis is confirmed by genetic testing.
• A small cerebellum and large brain ventricles can be seen on brain imaging (MRI).

Treatment

Treatment is supportive and includes physical, occupational and speech and language therapy.

Hereditary disease

NIH genetic and rare disease info

• NIH info on OPHN1 syndrome

OPHN1 syndrome is a rare disease.

OPHN1 syndrome Resources
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