1/4. Compound heterozygosity for a recurrent 16.5-kb Alu-mediated deletion mutation and single-base-pair substitutions in the ABCC6 gene results in pseudoxanthoma elasticum.pseudoxanthoma elasticum (PXE) is a systemic heritable disorder affecting the elastic structures in the skin, eyes, and cardiovascular system, with considerable morbidity and mortality. Recently, mutations in the ABCC6 gene (also referred to as "MRP6" or "eMOAT") encoding multidrug-resistance protein 6 (MRP6), a putative transmembrane ABC transporter protein of unknown function, have been disclosed. Most of the genetic lesions delineated thus far consist of single-base-pair substitutions resulting in nonsense, missense, or splice-site mutations. In this study, we examined four multiplex families with PXE inherited in an autosomal recessive pattern. In each family, the proband was a compound heterozygote for a single-base-pair-substitution mutation and a novel, approximately 16.5-kb deletion mutation spanning the site of the single-base-pair substitution in trans. The deletion mutation was shown to extend from intron 22 to intron 29, resulting in out-of-frame deletion of 1,213 nucleotides from the corresponding mRNA and causing elimination of 505 amino acids from the MRP6 polypeptide. The deletion breakpoints were precisely the same in all four families, which were of different ethnic backgrounds, and haplotype analysis by 13 microsatellite markers suggested that the deletion had occurred independently. Deletion breakpoints within introns 22 and 29 were embedded within AluSx repeat sequences, specifically in a 16-bp segment of dna, suggesting Alu-mediated homologous recombination as a mechanism.- - - - - - - - - - ranking = 1keywords = cardiovascular system (Clic here for more details about this article) |
2/4. Intravascular ultrasound findings of coronary wall morphology in a patient with pseudoxanthoma elasticum.pseudoxanthoma elasticum (PXE) is an inherited disorder characterised by progressive calcification of the elastic fibres in the skin, eye, and cardiovascular system. Recently, mutations in the ATP binding cassette transporter gene (ABCC6) were identified as cause of this disease. Although patients with PXE often have coronary artery disease, little is known about the process and the mechanism of coronary artery disease in PXE. In this report, intravascular ultrasound (IVUS) imaging was performed in a female patient with PXE seven years after the onset of skin lesion to assess the coronary wall morphology in detail. IVUS showed a unique five layer appearance without acoustic shadowing along the vessel wall observed in the angiographically normal portion. These findings may reflect the earlier stage of coronary artery disease caused by PXE before calcification of the internal elastic laminae.- - - - - - - - - - ranking = 1keywords = cardiovascular system (Clic here for more details about this article) |
3/4. Identification of two novel missense mutations (p.R1221C and p.R1357W) in the ABCC6 (MRP6) gene in a Japanese patient with pseudoxanthoma elasticum (PXE).pseudoxanthoma elasticum (PXE) is a rare, inherited, systemic disease of elastic tissue that in particular affects the skin, eyes, and cardiovascular system. Recently, the ABCC6 (MRP6) gene was found to cause PXE. A defective type of ABCC6 gene (16pl3.1) was determined in two Japanese patients with PXE. In order to determine whether these patients have a defect in ABCC6 gene, we examined each of 31 exons and flanking intron sequences by PCR methods (SSCP screening and direct sequencing). We found two novel missense variants in exon 26 and 29 in a compound heterozygous state in the first patient. One is a missense mutation (c.3661C>T; p.R1221C) in exon 26 and the other is a missense mutation (c.4069C>T; p.R1357W) in exon 29. These mutations have not been detected in our control panel of 200 alleles. To our knowledge, this is the first report of mutation identification in the ABCC6 gene in Japanese PXE patients. The second patient was homozygous for 2542_2543delG in ABCC6 gene and heterozygous for 6 kb deletion of LDL-R gene. This case is the first report of a genetically confirmed case of double mutations both in PXE and FH loci.- - - - - - - - - - ranking = 1keywords = cardiovascular system (Clic here for more details about this article) |
4/4. Periumbilical pseudoxanthoma elasticum with systemic manifestations.We have reviewed the typical clinical manifestations of pseudoxanthoma elasticum and presented the case of a patient with involvement of the skin, eyes, and cardiovascular system. We suggest that patients with periumbilical lesions that might indicate pseudoxanthoma elasticum have, at minimum, a full physical examination with emphasis on the cardiovascular system and a complete ophthalmologic evaluation.- - - - - - - - - - ranking = 2keywords = cardiovascular system (Clic here for more details about this article) |