Expanding the phenotypic spectrum of L1CAM-associated disease

Area of Science:

• Genetics
• Neurology
• Developmental Biology

Background:

• Mutations in the L1 Cell Adhesion Molecule (L1CAM) gene are linked to a spectrum of neurological disorders.
• These disorders exhibit significant inter- and intrafamilial variability.
• Previous studies suggest a potential link between L1CAM mutations and Hirschsprung's disease (HSCR).

Observation:

• Two siblings with a missense mutation (p.P240L) in exon 7 of the L1CAM gene were identified.
• One sibling presented with congenital dislocation of the radial heads and HSCR.
• Both siblings displayed a hypoplastic corpus callosum, but lacked hydrocephalus, adducted thumbs, or absent speech.

Findings:

• The identified L1CAM p.P240L mutation is associated with a distinct phenotype.
• This phenotype includes corpus callosum hypoplasia and, in one case, HSCR and radial head dislocation.
• The findings expand the known spectrum of L1CAM-associated abnormalities.

Implications:

• L1CAM mutation analysis should be considered in males with a family history suggestive of X-linked inheritance.
• Testing is recommended for individuals presenting with agenesis of the corpus callosum (CC) combined with HSCR or limb abnormalities.
• This aids in diagnosing complex neurodevelopmental disorders and understanding genotype-phenotype correlations in L1CAM-related conditions.