Prenatal Diagnosis and Testing for X-Linked Ichthyosis
Low estriol levels detected in prenatal screenings can be a marker for X-linked ichthyosis. Ichthyosis is a family of rare genetic skin diseases, characterized by thick, dry, cracked, and scaling skin. The genetic defect in X-linked ichthyosis causes a deficiency of the enzyme steroid sulfatase. X-linked ichthyosis is considered one of the more mild forms of ichthyosis and is treatable with topical creams and lotions. Children with X-linked ichthyosis often appear normal at birth. Several days following birth the skin typically peels and flakes in an exaggeration of the normal pattern of neonatal desquamation. Afterward, dry flaky scales are usually present on the trunk and arms and legs. The symptoms of this form of ichthyosis are largely limited to the skin; that is X-linked ichthyosis does not cause neurological or developmental impairments. However, there is an increased incidence of cryptorchidism (failure of the testes to descend from the abdomen to the scrotum during development.
The genetic defect in X-linked ichthyosis causes a deficiency of the enzyme steroid sulfatase. Low estriol levels detected in prenatal screenings indicate X-linked ichthyosis in the fetus.
Fluorescent In Situ Hybridization (FISH) testing for the steroid sulfatase gene deletion can confirm X-linked ichthyosis in the suspected fetus or child. However, FISH testing can miss up to 10 % of individuals with X-linked ichthyosis. If the FISH is negative and the index of suspicions is high for X-linked ichthyosis, further testing in the form of an enzyme assay for steroid sulfatase activity is indicated.
Genomic microarray analysis can detect almost all disorders detected by standard cytogenetic analysis and multiple FISH tests.
The following laboratories are resources for the testing that can confirm a diagnosis of X-linked ichthyosis.
A listing is also available on the website, www.genetests.org.
Quest Diagnostics, Inc.
Cytogenetics Laboratory
Van Nuys, CA
Main: 800.339.4299
818.779.1582 for specimen & shipping requirements, and costs—draw station
Specialty Laboratories, Inc.
Cytogenetics Laboratory
Santa Monica, CA
800.421.4449 for specimen & shipping requirements, and costs
www.specialtylabs.com
Canada
The Credit Valley Hospital
Genetics Laboratory
Mississauga, Ontario, Canada
905.813.4104 for specimen & shipping requirements, and costs
www.cvh.on.ca/
Florida
All Children's Hospital
Cytogenetics and Molecular Genetics Laboratory
St. Petersburg, FL
727.767.8559 for specimen & shipping requirements, and costs
Email: sutcliff@allkids.org
Indiana
Indiana University School of Medicine
Cytogenetics Laboratory
Indianapolis, IN
317.274.2241 for specimen & shipping requirements, and costs
Louisiana
Tulane University School of Medicine
Hayward Genetics Center Cytogenetics Lab
New Orleans, LA
504.988.5229 for specimen & shipping requirements, and costs
www.haywardgenetics.tulane.edu
Massachusetts
Boston University School of Medicine
Center for Human Genetics
Boston, MA
617.638.7083 for specimen & shipping requirements, and costs
Brigham and Women’s Hospital
Cytogenetics Laboratory
Boston, MA
857.307.1500
617.732.7981 for specimen & shipping requirements, and costs
www.brighamandwomens.org/cytogenetics/#
Minnesota
Mayo Clinic
Cytogenetics Laboratory
Rochester, MN
800.533.1719 for specimen & shipping requirements, and costs
Email: mml@mayo.edu
Mayo Medical Laboratories International
US access # plus 507-266-5700
Email: mmlglobal@mayo.edu
Montana
Shodair Hospital
Genetics Laboratory
Helena, MT
800.447.6614 Hospital switchboard number
406.444.7532 Lab
Email: mtgene@shodair.org
Nebraska
University of Nebraska Medical Center
Human Genetics Laboratory, Munroe–Meyer Institute
Omaha, NE
402.559.5229 specimen & shipping requirements, and costs
Email: rfordyce@unmc.edu
www.unmc.edu/services/geneticslab
SUNY Upstate Medical University
Cytogenetics Laboratory
Syracuse, NY
877.464.4716 for specimen & shipping requirements, and costs
North Carolina
GeneCare Medical Genetics
Molecular Cytogenetics Laboratory
Chapel Hill, NC
919.942.0021
800.277.4363 for specimen & shipping requirements, and costs
www.genecare.com
Wake Forest University School of Medicine
Section of Medical Genetics
Winston-Salem, NC
866.487.2344 Toll Free
336.713.7500 for specimen & shipping requirements, and costs
Email Kris Morris cmorris@wfubmc.edu
Ohio
Columbus Children’s Hospital
Cytogenetics Laboratory
Columbus, OH
Edie Paal, Lab Coordinator
614.722.5321 specimen & shipping requirements, and costs
www.childlab.com
Tennessee
Genetics Associates, Inc.
Nashville, TN
615.327.4532
800.331.GENE (4363) for specimen & shipping requirements, and costs
www.geneticsassociates.com
T.C. Thompson Children’s Hospital
Genetic Diagnostic Laboratory
Chattanooga, TN
423.778.6279 for specimen & shipping requirements, and costs
Texas
Baylor College of Medicine
Cytogenetics Laboratory
Houston, TX
713.798.6555 for for specimen & shipping requirements, and costs
800.411.GENE (4363)
Email: genetictest@bcm.tmc.edu
Virginia
Quest Diagnostics, Inc.
Cytogenetics Laboratory
Chantilly, VA
703.802.7100 for specimen & shipping requirements, and costs
Washington
Children’s Hospital and Regional Medical Center
Cytogenetics
Seattle, WA
206.987.2216 for specimen & shipping requirements, and costs
Sacred Heart Medical Center
Cytogenetics Laboratory
Spokane, WA
509.474.4441 for specimen & shipping requirements, and costs
Signature Genomic Laboratories
Spokane, WA
509.474.6840 for specimen & shipping requirements,and costs
Email: info@signaturegenomics.com
www.signaturegenomics.com
University of Washington Medical Center
Cytogenetics Laboratory
Seattle, WA
Christine Disteche, PhD
206.598.4488 for specimen & shipping requirements, and costs
www.uwmedicine.org
Biochemical Genetics
Houston, TX
713.798.6555 for specimen & shipping requirements, and costs
Biochemical Diagnostic Laboratory
Omaha, NE
Dr. William Rizzo - 402.559.5260, wrizzo@unmc.edu
Melanie Schrack - 402.559.2550
www.unmc.edu/services/geneticslab/Biochem.htm
Cytogenetics Laboratory
Houston, TX
Please call 800.411.4363 prior to sending a sample
www.bcmgeneticlabs.org/tests/cyto/cma.html
Spokane, WA
509.474.6840 specimen & shipping requirements, and costs
Email: info@signaturegenomics.com
www.signaturegenomics.com
