Mucopolysaccharidosis I (MPS I), Hurler Syndrome : IDUA Sequencing

Test Information

IDUA sequencing is a molecular test used to identify variants in the gene associated with Mucopolysaccharidosis I (MPS I), Hurler Syndrome.

Turnaround Time

3 weeks

CPT Code(s)

81406

Cost

$1,000

Genes

Clinical Information

Mucopolysaccharidosis type I (MPSI) is caused by deficient alpha-iduronidase enzyme activity, which results in an accumulation of the glycoamnioglycan heparan sulfate and dermatan sulfate in body tissues. MPS I is a multisystem progressive disorder demonstrating wide phenotypic variability with three different MPSI subtypes described (Hurler, Hurler-Scheie, and Scheie). Hurler syndrome is considered the more severe end of the phenotypic spectrum with patients generally diagnosed before 18 months of age while Hurler-Scheie and Scheie syndromes are usually used to describe the milder phenotypes. These less severe cases, also known as attenuated MPS I, will often present between 3 and 10 years of age. Clinical features of MPS I include coarse facial features, dysostosis multiplex, short stature, hirsutism, cloudy corneas, and hepatosplenomegaly, and cardiac comlications. Developmental delay and intellectual disability is more severe in those patients with Hurler syndrome and is a distinguishing feature between the subtypes of MPS I.

Mucopolysaccharidosis type I (MPSI) is caused by deficient L-iduronidase enzyme activity, which results in an accumulation of the glycoamnioglycan heparan sulfate and dermatan sulfate in body tissues. MPS I is a multisystem progressive disorder demonstrating wide phenotypic variability with three different MPSI subtypes described (Hurler, Hurler-Scheie, and Scheie). Hurler syndrome is considered the more severe end of the phenotypic spectrum with patients generally diagnosed before 18 months of age while Hurler-Scheie and Scheie syndromes are usually used to describe the milder phenotypes. These less severe cases, also known as attenuated MPS I, will often present between 3 and 10 years of age. Clinical features of MPS I include coarse facial features, dysostosis multiplex, short stature, hirsutism, cloudy corneas, and hepatosplenomegaly, and cardiac comlications. Developmental delay and intellectual disability is more severe in those patients with Hurler syndrome and is a distinguishing feature between the subtypes of MPS I.

Indications

Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.

Methodology

Sanger Sequencing

Detection

Sequencing of the gene will detect about 97% of abnormal alleles in individuals with a biochemical diagnosis.

Specimen Requirements

5 to 7 ml of peripheral blood collected in an EDTA (lavender top) tube is the preferred specimen type. The minimal blood needed for reliable DNA isolation is 3 ml. Extracted DNA, dried blood spots, and saliva are also accepted for this test.

Transport Instructions

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Prenatal Testing Information

Prenatal diagnosis is available if the familial mutations are known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Molecular Testing, Newborn Screening Follow-Up, Sanger Sequencing
Meet The Jones Family

Meet The Jones Family

The journey to becoming parents did not start as an easy one for my husband and I. We suffered the heartache of miscarriage and the unimaginable pain of burying our first born child. Our son, sweet 1 lb 1.4 ounce, 12 inches long, teeny, tiny little Joseph “Hamilton” Jones was born with spina bifida, hydrocephalus, and a heart defect. It tore our hearts out leaving the hospital without him, knowing our dreams and hope for the future were shattered. ...

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