Last updated 14d ago
Log in to add personal notes on this page.
A male infant is born with severe hydrocephalus requiring shunting. He has adducted thumbs and later develops spastic paraplegia. Family history is notable for 2 affected maternal uncles with similar symptoms.
XLR; L1CAM gene
- Hydrocephalus (aqueductal stenosis) → extra "L1quid" in the brain
- "L1": Leg spasticity + 1ntellectual disability
- Adducted (clasped) thumbs (affects "1st" digit)
- Spastic paraplegia (MASA syndrome = milder variant)
- Agenesis of corpus callosum
- Suspect in males with congenital hydrocephalus (aqueductal stenosis), adducted thumbs, and spasticity, especially with an X-linked family history
- Brain MRI: aqueductal stenosis, hydrocephalus, and corpus callosum hypoplasia/agenesis
- Confirm with molecular testing of L1CAM; spectrum spans L1 syndrome and the milder MASA phenotype
- Carrier testing of at-risk female relatives and prenatal/preimplantation testing once the familial variant is known
- Neurosurgical CSF shunting for symptomatic hydrocephalus
- Multidisciplinary supportive care: physical/occupational therapy and spasticity management (orthotics, baclofen, botulinum toxin)
- Developmental and educational support for intellectual disability
- Genetic counseling for X-linked recessive inheritance (carrier mothers, 50% risk to sons)
"L1quid in the brain": Hydrocephalus (extra "L1quid") causes macrocephaly.
"1st digit": Adducted (clasped) thumbs affect the "1st" digit.
"Leg spasticity, 1ntellectual disability": The "L" and "1" in L1 represent the two key neurological features.