Résumé :
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Communication n° 3 Abstract Two Iranian cases with very rare progeroid syndromes are reported. The first was a 24-year-old young girl. She was healthy till her 13th birthday. From that time she has been suffering gradually from a progressive generalized and multi-systemic illness. The cardinal clinical findings were: growth retardation, subcutaneous fat loss, skin dryness and wrinkling, scattered focal sclerodermoid like changes, prominence of superficial vessels, gradual loss of scalp hair and eyebrows, cardiac involvement as dilated cardiomyopathy. All the above findings were suggestive of precocious ageing. Our clinical impression was Werner's syndrome. The second case was a 6-year-old boy with typical clinical findings of Progeria or Hutchinson-Guilford syndrome. The diagnoses confirmed by molecular analysis of the samples in Washington and Marseille. In the first case there was no molecular abnormality in the Werner's gene (WRN). But a mutation was found in the LMNA gene : a substitution of C to G in codon number 57. And this codon; (GCA, alanine) changed to (CCA, proline). So, in the codon 57 of the protein Lamin A/C there is proline instead of alanine (A57>P). The mutation of the second case (Progeria=Hutchinson-Guilford syn.) was a point mutation at the exon 11 of Lamin A/C protein and one molecule thymine replaced by a cytosine in the nucleotide number 1824(1824C>T). Very different clinical entities correspond to missense mutations in the LMNA gene. These disorders are called Laminopathies. Most of them belong to the neuromuscular disorders. Emery-Drifuss X-Linked muscular dystrophy, type 1 dilated cardiomyopathy, Limb Girdle MD type B1, Charcot-Marie-Tooth disease type 2, are examples. The importance of lamins, the mechanism and pathogenesis of progeroid syndromes will be discussed briefly.
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