DNA Analysis Laboratory

The DNA Analysis Laboratory offers DNA testing services as second-tier testing in support of the Newborn Screening Program and for other individuals to determine carrier status or for mutational analysis. Tests are currently available for hemoglobinopathies, phenylketonuria, galactosemia, cystic fibrosis, and medium chain acyl-CoA dehydrogenase deficiency (MCADD).

Specimen Submission Form  (Use form G-1B) (only required for non-newborn screening specimens)

Required Sections for DNA test requests:

• Submitter Information
• Patient Information
• Payor Source
• DNA Analysis—test(s) requested

Send specimens to:

Specimen Acquisition
Texas Department of State Health Services
Laboratory Services Section
Mail Code 1947
PO Box 149347
Austin, TX 78714-9347

For contract and other information, call (512) 458-7430

Hemoglobinopathies

Mutations for hemoglobin types S, C, E, D-Los Angeles, and O-Arab, and two beta-thalassemia point mutations are detected by polymerase chain reaction and restriction fragment length polymorphism. Partial sequencing of the β-Globin gene is used for identification of other mutations. Specimens from the newborn screening program that test positive for specific hemoglobinopathies are referred for confirmatory DNA testing. Fee-for-service testing is also available. Click for more information

Phenylketonuria (PKU)

Mutations in the phenylalanine hydroxylase gene are identified by direct sequencing. Ninety-nine percent of PKU cases are caused by deficiencies of the enzyme phenylalanine hydroxylase. This test is available on a fee-for-service basis only. The reflex PKU DNA testing for diagnosed cases in support of the newborn screening program was discontinued effective October 1, 2008. Click for more information

Galactosemia

Common mutations/variants in the galactose-1-phosphate uridyl transferase (GALT) gene are identified by a tetra-primer amplification refractory mutation system-polymerase chain reaction. The mutation detection rate is estimated to be 70 percent in Caucasians but reduced in other ethnic groups. Specimens from the newborn screening program that test abnormal for GALT enzyme activity are referred for confirmatory DNA testing. Fee-for-service testing is also available. Click for more information

Cystic Fibrosis (CF)

Forty common mutations in the cystic fibrosis transmembrane conductance (CFTR) regulator gene are identified by multiplex polymerase chain reactions and fluorescent signal detection. The mutation detection rate is estimated to be 38.7-89.12 percent, depending on the patient's ethnicity. Selected specimens from the newborn screening program with an abnormal immunoreactive trypsinogen level are referred for DNA testing. Fee-for-service testing is also available. 

Medium Chain Acyl-CoA Dehydrogenase Deficiency (MCADD)

Four common mutations in the medium chain acyl-CoA dehydrogenase gene are identified by Real-Time polymerase chain reaction. The mutation detection rate is estimated to be 86 percent of disease alleles in the Texas population. Specimens from the Newborn Screening Program with presumtive positive results for MCADD are referred for the second-tier DNA testing. Fee-for-service testing is also available. 

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