GENE EXPRESSION OF EXTRACELLULAR MATRIX PROTEINS IN MARFAN
SYNDROME: POTENTIAL DIAGNOSTIC ROLE. M. West*, S. LeBrocque, M. Nataatmadja, K. Summers. Dept Medicine, Prince Charles Hospital, Brisbane, Qld. Marfan syndrome (MS) is an autosomal dominant inherited
disorder with high morbidity particularly the cardiovascular system, the
skeleton and the eyes. Within families
individuals may present with differing severity of the disorder leading to
difficulty in diagnosis in some family members. The condition is linked to mutations in the gene encoding the
protein fibrillin, a component a microfibrils in tissue extracellular
matrix. However, since mutations are
unique to each family and are distributed throughout the gene, screening for
mutations as a diagnostic tool is problematic.
In this study we have investigated the use of molecular techniques as
aids in the diagnosis of MS. Cultured fibroblasts from 11 subjects with MS (30-50 yr,
diagnosis according to the de Paepe et al (1996) criteria) were compared with
16 non MS subjects (30-80 yr).
Fibroblasts were derived from a skin biopsy and grown in cell culture to
confluence before subculture. The
subcultures were incubated for 12 h for RNA analysis and for 7 days for
immunohistochemistry. The relative intracellular
and extracellular localization of the extracellular matrix proteins fibrillin,
fibronectin and tenascin in the cultured fibroblasts for each subject was
determined using specific immunohistochemical markers. Matrix protein mRNA
levels were measured using conventional RT-PCR and "real time" quantitative
PCR. Immunohistochemical studies showed qualitative differences
in the distribution of extracellular matrix proteins with intracellular
retention of protein in subjects with MS compared to normals. In addition higher levels of mRNA were
present in subjects with MS compared to normals. Gene expression characteristics in cultured skin fibroblasts may
be useful in MS families for screening subjects with suspicion of MS.
