Familial Dysautonomia, DNA Analysis

CPT: 81260
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Test Details

Synonyms

  • 2507+6 T>C
  • IVS20+6T>C
  • Jewish Heritage Test
  • Riley-Day Syndrome

Use

Carrier detection of familial dysautonomia in the Ashkenazi Jewish population. DNA testing may be used to confirm affected status. Prenatal testing is available.

Limitations

This test has limited value in individuals who are not of Ashkenazi Jewish descent. This assay detects two mutations, IVS20+6T>C and R696P. No other mutations are detected.

Methodology

Polymerase chain reaction (PCR); primer extension; flow-sorted bead array analysis

Additional Information

Familial dysautonomia (OMIM 223900), also known as Riley-Day syndrome, is an autosomal recessive disorder that is characterized by absence of papillae of the tongue, decreased tearing, erythematous blotching of the skin, difficulties with swallowing, relative insensitivity to pain, and reduced life expectancy. The mutation detection rate for this assay varies with ethnicity. Two mutations have been found to be responsible for the majority of familial dysautonomia cases in the Ashkenazi Jewish population, with approximately 1 in 30 individuals being carriers. The mutation detection rate is negligible among non-Jewish Caucasians and unknown in other ethnic groups. For this reason, this test has limited value for people of non-Ashkenazi Jewish ancestry. DNA test results must be combined with clinical information for the most accurate interpretation.

Specimen Requirements

Specimen

Whole blood, amniotic fluid, chorionic villus sample (CVS) (submission of maternal blood is required for fetal testing), or LabCorp buccal swab kit (buccal swab collection kit contains instructions for use of a buccal swab)

Volume

7 mL whole blood, 10 mL amniotic fluid, 20 mg CVS, or LabCorp buccal swab kit

Minimum Volume

3 mL whole blood, 5 mL amniotic fluid, 10 mg CVS, or two buccal swabs

Container

Lavender-top (EDTA) tube, yellow-top (ACD) tube, sterile plastic conical tube or two confluent T25 flasks for fetal testing, or LabCorp buccal swab kit

Storage Instructions

Maintain specimen at room temperature.

Causes for Rejection

Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container; one buccal swab; wet buccal swab

Clinical Information

References

American College of Obstetricians and Gynecologists Committee on Genetics. ACOG committee opinion. Nº 298, August 2004. Prenatal and preconceptional carrier screening for genetic diseases in individuals of Eastern European Jewish descent. Obstet Gynecol. 2004 Aug; 104(2):425-428. 15292027
Anderson SL, Coli R, Daly IW, et al. Familial dysautonomia is caused by mutations of the IKAP gene. Am J Hum Genet. 2001 Mar; 68(3):753-758. 11179021
Dong J, Edelmann L, Bajwa AM, Kornreich R, Desnick RJ. Familial dysautonomia: Detection of the IKBKAP IVS20+6T→C and R696P mutations and frequencies among Ashkenazi Jews. Am J Med Genet. 2002; 110(3):253-257. 12116234
Monaghan KG, Feldman GL, Palomaki GE, Spector EB; Ashkenazi Jewish Reproductive Screening Working Group; Molecular Subcommittee of the ACMG Laboratory Quality Assurance Committee. Technical standards and guidelines for reproductive screening in the Ashkenazi Jewish population. Genet Med. 2008 Jan; 10(1):57-72. 18197058
Slaugenhaupt SA, Blumenfeld A, Gill SP, et al. Tissue-specific expression of a splicing mutation in the IKBKAP gene causes familial dysautonomia. Am J Hum Genet. 2001 Mar; 68(3):598-605. 11179008

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
511352 Familial Dysautonomia, DNA 511355 Familial Dysautonomia 32653-8
511352 Familial Dysautonomia, DNA 511947 PDF 51969-4
511352 Familial Dysautonomia, DNA 511005 Jewish Heritage Putaway N/A

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