X-Linked Opitz G/BBB syndrome : MID1 Sequencing

Test Information

MID1 sequencing is a molecular test used to identify variants in the gene associated with X-Linked Opitz G/BBB syndrome.

Turnaround Time

6 weeks

CPT Code(s)





Clinical Information

Males with X-linked Opitz G/BBB syndrome have multiple congenital anomalies such as genitourinary abnormalities, laryngo-tracheo-esophageal defects, cleft lip and/or palate, heart defects, anus anomalies, and midline brain defects. In addition, these individuals have a characteristic facial appearance and less than 50% will have developmental delay or intellectual disability. Female carriers often only manifest the ocular hypertelorism.


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.


Sanger Sequencing


Sequencing of the MID1 gene will detect mutations in 15-50% of individuals with G/BBB syndrome.

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

Sanger Sequencing, Test Finder
Meet Makayla Gunn

Meet Makayla Gunn

Makayla was diagnosed with Rett Syndrome in April of 2015 at the age of two.   At about 18 months, we noticed she had started some repetitive hand motions, and her pediatrician was a little concerned that she did not have many words.  She had learned some sign language, and was saying ‘mama’ and ‘dada’, but that was it.  Then she suddenly stopped all of that.  At her 2 year old check-up, the pediatrician referred us to BabyNet, ...

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