Automated direct sequencing of the iduronate-2 sulfatase gene reveals a vast spectrum of mutations causing Hunter syndrome (mucopolysaccharidosis type II) and a {open_quotes}hot spot{close_quotes} at R468

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:134359

Whitley, C B; Jonsson, J J; Aronovich, E L ^[1]

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1. Univ. of Minnesota Medical School, Minneapolis, MN (United States)

Hunter syndrome is an X-linked recessive, lethal disease resulting from deficiency of iduronate-2-sulfatase (IDS) catalytic activity. Because of low reproductive fitness, most affected individuals are expected to have new mutations. Most of such defects are anticipated to be single base pair (bp) changes; however, several previous studies utilizing Southern analysis of RT-PCR have identified numerous large gene deletions in patients having the {open_quotes}severe form{close_quotes} with neurologic disease. To investigate the spectrum of IDS mutations, we have developed a method of automated direct sequencing of RT-PCR products representing the entire IDS coding region. Of 19 patients studied by this approach, only 1 had an IDS coding region which did not contain a mutation; 1 had a single bp insertion; 1 had a 2 bp deletion; and 13 had single-base substitutions. Of the 13 having single base substitutions, 2 resulted in aberrant splicing. Only 1 patient had a complete gene deletion; in view of previous reports, there was a surprising lack of major gene deletions. Notably, a CpG dinucleotide at R468 was identified as a {open_quotes}hot spot{close_quotes} for mutation. Five unrelated individuals had substitutions at this site which thus accounted for 28% of all mutations in this series: R468W (3 patients) and R468Q (2 patients). MspI digestion provided a method of rapid diagnosis and determination of heterozygote status for such R468 mutations. Genotype-phenotype correlations in this R468 group are not yet possible because of confounding information, i.e., there are both {open_quotes}mild{close_quotes} and {open_quotes}severe{close_quotes} patients in this group and some have co-existing neurologic diseases. This approach of gene sequencing appears to be necessary, and sufficient, to characterize the vast spectrum of mutations in Hunter syndrome.

• OSTI ID: 134359
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
AUTOMATION
DETECTION
DNA SEQUENCING
ENZYMES
GENE MUTATIONS
GENES
HEREDITARY DISEASES
HUMAN X CHROMOSOME
LETHAL MUTATIONS
METABOLIC DISEASES
NERVOUS SYSTEM DISEASES
NUCLEOTIDES
PATIENTS
POLYMERASE CHAIN REACTION
RECESSIVE MUTATIONS
SIZE
SPLICING