Bergmann C, Küpper F, Schmitt C P, Vester U, Neuhaus T J, Senderek J, Zerres K
Department of Human Genetics, Aachen University, Germany.
J Med Genet. 2005 Oct;42(10):e63. doi: 10.1136/jmg.2005.032318.
Autosomal recessive polycystic kidney disease (ARPKD) is caused by mutations in the PKHD1 (polycystic kidney and hepatic disease 1) gene on chromosome 6p12, a large gene spanning 470 kb of genomic DNA. So far, only micromutations in the 66 exons encoding the longest open reading frame (ORF) have been described, and account for about 80% of mutations.
To test the hypothesis that gross genomic rearrangements and mutations in alternatively spliced exons contribute to a subset of the remaining disease alleles.
Using DHPLC for alternatively spliced exons and quantitative real time polymerase chain reaction to detect genomic imbalances, 58 ARPKD patients were screened, of whom 55 were known to harbour one PKHD1 point mutation in the longest ORF.
Three different heterozygous PKHD1 deletions and several single nucleotide changes in alternatively spliced exons were identified. The detected partial gene deletions are most likely pathogenic, while a potential biological function of the alterations identified in alternatively spliced exons must await the definition of transcripts containing alternative exons and their predicted reading frames.
Gross PKHD1 deletions account for a detectable proportion of ARPKD cases. Screening for major genomic PKHD1 rearrangements will further improve mutation analysis in ARPKD.
常染色体隐性多囊肾病（ARPKD）由位于6号染色体短臂12区的PKHD1（多囊肾和肝病1）基因突变引起，该基因是一个跨越470kb基因组DNA的大基因。到目前为止，仅描述了编码最长开放阅读框（ORF）的66个外显子中的微小突变，这些突变约占所有突变的80%。
验证大片段基因组重排和可变剪接外显子中的突变导致了一部分剩余疾病等位基因的假设。
使用变性高效液相色谱法检测可变剪接外显子，并采用定量实时聚合酶链反应检测基因组失衡，对58例ARPKD患者进行筛查，其中55例已知在最长ORF中存在一个PKHD1点突变。
鉴定出三种不同的杂合性PKHD1缺失以及可变剪接外显子中的几个单核苷酸变化。检测到的部分基因缺失很可能具有致病性，而在可变剪接外显子中鉴定出的改变的潜在生物学功能必须等待包含可变外显子及其预测阅读框的转录本的定义。
PKHD1大片段缺失在ARPKD病例中占可检测比例。筛查PKHD1主要基因组重排将进一步改善ARPKD的突变分析。
