Characterization of a partial pseudogene homologous to the Hermansky-Pudlak syndrome gene HPS-1; Relevance for mutation detection

Marjan Huizing, Yair Anikster, William A. Gahl*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The HPS-1 gene is the first gene found to be responsible for the autosomal recessive disorder Hermansky-Pudlak syndrome (HPS). HPS is characterized by oculocutaneous albinism, a platelet storage pool deficiency, and ceroid lipofuscinosis. The HPS-1 gene has been mapped to chromosome 10q23.1-23.3 and encodes a 79-kDa protein of unknown function with no homology to any known protein. A sequence database search has revealed that a portion of clone HS1119A7 shows high sequence similarity to HPS-1 cDNA. By performing sequence alignments and PCR amplification of cDNA from several human tissues, we have shown that part of this clone consists of an unprocessed partial HPS-1 pseudogene located on chromosome 22q12.2-12.3. The pseudogene contains several intact HPS-1 exons and shows 95% sequence homology to the HPS-1 cDNA. Exon 6 of the pseudogene has 100% sequence homology to exon 6 of HPS-1 itself. In the pseudogene, this exon is surrounded by portions of both its normal flanking introns. These data provide the first characterization of an HPS-1 pseudogene, called HPS1-ψ1. During amplification of exon 6 of the HPS-1 gDNA for mutation identification, the pseudogene might also be amplified, leading to a false positive for mutation. In addition, amplification of specific parts of the HPS-1 cDNA (e.g., exons 2-5) for mutation detection might lead to false positives for mutations, if the cDNA is contaminated with gDNA. This calls for caution when employing these screening approaches.

Original languageEnglish
Pages (from-to)370-373
Number of pages4
JournalHuman Genetics
Volume106
Issue number3
DOIs
StatePublished - 2000
Externally publishedYes

Funding

FundersFunder number
Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentZIAHD001607, Z01HD000131

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