MASP1encodes a serine protease involved in the lectin complement pathway, a part of the innate immune system. Along with COLEC11and COLEC10, it also contributes to neural crest cell migration during embryogenesis. Biallelic pathogenic variants in any of these three genes can lead to 3MC syndrome.
Disease-causing MASP1variants include nonsense, frameshift, missense, and splice-site mutations, as well as deletions. Inheritance is autosomal recessive. A clear genotype–phenotype correlation has not yet been established.
Diagnosis / Testing
Molecular testing for 3MC syndrome should include MASP1, COLEC11, and COLEC10. Diagnostic approaches typically involve targeted gene panels or exome/genome sequencing. If single nucleotide variants are not detected, deletion/duplication analysis may be required to identify copy number changes.
MASP1