Severe intellectual disability-progressive spastic diplegia syndrome is a rare novel genetic disorder characterized by severe intellectual disabilities, ataxia, craniofacial dysmorphisms, and muscle spasticity. It is a type of autosomal dominant syndromic intellectual disability.
Signs and symptoms
Individuals with this condition typically show severe intellectual disability, motor delays, severe speech delay and difficulties, infancy-onset hypotonia affecting the trunk, progressive hypertonia affecting the distal limbs, severe progressive microcephaly, autistic-like symptoms, aggressive behavior towards others and/or oneself, sleep abnormalities, and mild facial dysmorphisms such as a broad nose, hypoplastic alae nasi, an elongated/flattened philtrum, and a thin upper lip.
Other symptoms include seizures, nearsightedness, farsightedness, strabismus, syringomyelia, ventriculomegaly, corpus callosum hypoplasia, hearing difficulties, and a delay in CNS myelination.
In rarer cases, a child with the condition might be born with polydactyly.
Complications
Most symptoms which characterize this condition arise as a result of the profound intellectual disability associated with this condition, these symptoms can cause more complications, such as communication difficulties, poor school performance, etc.
Diagnosis
This condition can be diagnosed through physical examination and genetic testing.
Genetics
This condition is caused by heterozygous mutations in the CTNNB1 gene, located in the short arm of chromosome 3. The condition, although genetic, is typically not inherited, except in rare cases where it is, as it is usually the result of a de novo mutation. Insertions, deletions, and other types of mutations have been reported.
This gene produces a protein called "beta-catenin", which is present in various cells and tissues within the body. It is important for cell adhesion, cell communication, cell signaling, and in the normal development and function of hair follicles.
Treatment
Treatment methods include occupational therapy, physical therapy, speech therapy, assistive services, constant monitoring and family counseling.
Prevalence
This condition affects 1 out of 50,000 children worldwide.
Cases
The following list comprises some cases of severe intellectual disability-progressive spastic diplegia syndrome (from the OMIM page for this condition):