Prenatal diagnosis of L1 cell adhesion molecule mutations: Capabilities and limitations

Discuss the capability for and limitations of prenatal detection of L1 cell adhesion molecule (L1CAM) mutations. Haplotype analysis by PCR and PAGE. Mutation detection by SSCP, followed by dideoxy sequencing. Confirmation of sequencing results with PCR and NcoI digestion. A 1-bp deletion was found in exon 2 of L1CAM in all affected males and obligate carriers in the pedigree. Prenatal detection is now possible for subsequent pregnancies. In a large gene with widespread mutations such as L1CAM, a mutation must be detected in another family member before direct prenatal mutation testing can be done within the required timeframe. If the proper family members are available, haplotyping offers a fast but indirect test with several limitations.