Severe Alport syndrome in a young woman caused by a t(X;1)(q22.3;p36.32) balanced translocation

Kazumoto Iijima, Kandai Nozu, Koichi Kamei, Makiko Nakayama, Shuichi Ito, Kentaro Matsuoka, Tsutomu Ogata, Hiroshi Kaito, Koichi Nakanishi, Masafumi Matsuo

    Research output: Contribution to journalArticlepeer-review

    10 Citations (Scopus)

    Abstract

    The course of renal involvement and hearing loss is much milder in most female X-linked Alport syndromes than in male patients. We examined the molecular mechanism of development of the disease in a female patient with severe Alport syndrome. The patient showed heavy proteinuria, hematuria, neurosensory hearing loss and primary amenorrhea. Renal biopsy findings of electron microscopy and immunostaining of the α5 chain of type IV collagen indicated a female X-linked Alport syndrome. G-banding chromosomal analysis showed a t(X;1)(q22.3;p36.32) balanced translocation. Analysis of the collagen type IV (COL4A5) gene by genomic DNA sequencing, complementary DNA (cDNA) sequencing and multiplex ligation-dependent probe amplification assay showed no mutations or deletions/duplications of the gene. However, fluorescence in situ hybridization using the probes for exon 1 and exon 51 of the COL4A5 gene showed disruption of one copy of the gene. Replication R-banding chromosomal analysis indicated preferential inactivation of the normal X chromosome. This is the first report of severe Alport syndrome in a female patient carrying a balanced translocation between the chromosome X and 1 producing the disruption of one copy of COL4A5 gene and silencing of the other copy because of preferential inactivation of the normal X chromosome. Chromosomal abnormalities should be considered in female patients with severe forms of Alport syndrome.

    Original languageEnglish
    Pages (from-to)2165-2170
    Number of pages6
    JournalPediatric Nephrology
    Volume25
    Issue number10
    DOIs
    Publication statusPublished - 2010 Oct

    Keywords

    • Alport syndrome
    • Balanced translocation
    • Chromosomal abnormalities
    • Female
    • Gonadal dysgenesis
    • X inactivation

    ASJC Scopus subject areas

    • Pediatrics, Perinatology, and Child Health
    • Nephrology

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