Compound-heterozygous Marfan syndrome.

Area of Science:

• Genetics and Molecular Biology
• Human Genetics
• Connective Tissue Disorders

Background:

• Marfan syndrome (MFS) is a genetic disorder affecting connective tissue, primarily caused by mutations in the FBN1 gene.
• The inheritance pattern of MFS is typically autosomal dominant, with variable expressivity.

Observation:

• Two families presented with compound-heterozygous Marfan syndrome (MFS).
• Probands carried distinct FBN1 mutations on each allele, including R2726W.
• Phenotypic severity in compound heterozygotes was greater than in heterozygous relatives.

Findings:

• Compound-heterozygous MFS, involving two different FBN1 mutations, can lead to a more severe clinical presentation.
• The presence of specific FBN1 mutations may act as genetic modifiers, influencing the overall Marfan syndrome phenotype.
• This finding suggests a potential mechanism for the observed intrafamilial variability in Marfan syndrome.

Implications:

• Understanding compound heterozygosity in MFS is crucial for accurate diagnosis and prognosis.
• Identifying modifier FBN1 mutations could lead to more personalized treatment strategies for Marfan syndrome patients.
• This research highlights the complex genetic architecture underlying Marfan syndrome and connective tissue disorders.