Opitz G/BBB Syndrome is a genetic disorder that affects several different structures of the body, along the midline of the body.
What are the other Names for this Condition? (Also known as/Synonyms)
- Hypertelorism-Hypospadius Syndrome
- Telecanthus-Hypospadius Syndrome
What is Opitz G/BBB Syndrome? (Definition/Background Information)
- Opitz G/BBB Syndrome is a genetic disorder that affects several different structures of the body, along the midline of the body. These abnormalities affect the face, larynx, trachea, and in many cases, the genital area
- Two forms of Opitz G/BBB Syndrome are currently known. The X-linked form is caused by a mutation in the MID1 gene of the X chromosome. The autosomal dominant form of the disorder is caused by a deletion of 22q11.2 on chromosome 22
Who gets Opitz G/BBB Syndrome? (Age and Sex Distribution)
- X-linked Opitz G/BBB Syndrome rare disorder that affects 1 in 50,000-100,000 individuals. It is most commonly found in males.
- The incidence of autosomal dominant Opitz G/BBB Syndrome is largely unknown; though, it is estimated to be about 1 in 4,000 individuals
- Both males and females are susceptible to inheriting this form of the disorder
- No racial, ethnic, or geographical predilection is noted
What are the Risk Factors for Opitz G/BBB Syndrome? (Predisposing Factors)
Common risk factors of Opitz G/BBB Syndrome include:
- Parents with the disorder
- Parents, who are carriers of the disorder
It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.
Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.
What are the Causes of Opitz G/BBB Syndrome? (Etiology)
- X-linked Opitz G/BBB Syndrome is caused by a mutation on the MID1 gene of the X chromosome. In males, when the mutation is inherited, they will have the disorder because they only have one copy of the x chromosome. In females, only those with two copies of the mutation will have the disorder.
- Normally, the MID1 gene provides coding for making the protein midin. This protein helps regulate the function of microtubules and aids in the breakdown of the protein phosphatase 2A (PP2A) enzyme. When a mutation is present in this gene, PP2A accumulates in the cell, which negatively impacts the functioning of microtubule associated proteins.
Autosomal dominant Opitz G/BBB Syndrome is caused by the deletion of 22q11.2 on chromosome 22. If one mutated copy of the chromosome is inherited, an individual will get the disorder.
Little is known about this deletion and the genes that are associated with the loss of this segment of chromosome 22.
What are the Signs and Symptoms of Opitz G/BBB Syndrome?
Common signs and symptoms of Opitz G/BBB Syndrome include:
- Cleft lip
- Cleft palate
- Hypertelorism (wide-spaced eyes)
- Breathing problems
- Difficulty swallowing
- Prominent forehead
- Widow’s peak
- Urogenital abnormalities
- Heart defects
- Mild intellectual disabilities
How is Opitz G/BBB Syndrome Diagnosed?
- To diagnose Opitz G/BBB Syndrome, medical professionals will look for common signs and symptoms of the disorder after conducting a through physical examination and complete medical history
- To confirm the diagnosis, genetic testing may be conducted
Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.
What are the possible Complications of Opitz G/BBB Syndrome?
- Due to the abnormalities that can develop along the midline of the body, deformities are likely to occur. These can cause secondary complications, including:
- Difficulties breathing
- Speech problems
How is Opitz G/BBB Syndrome Treated?
- To treat Opitz G/BBB Syndrome, surgery is usually done. Surgery can be used to fix malformations that result from the disorder.
- Speech therapy is recommended as most individuals with the disorder have a cleft lip or cleft palate.
- Individuals with intellectual disabilities or lowered mental capacity, usually receive neuropsychological and educational support.
How can Opitz G/BBB Syndrome be Prevented?
- Opitz G/BBB Syndrome is a genetically inherited disorder. Currently, there is no way to prevent this disorder
- If you are at risk of passing it on, genetic counseling before getting pregnant is important in order to fully understand your options.
What is the Prognosis of Opitz G/BBB Syndrome? (Outcomes/Resolutions)
- The prognosis for individuals with Opitz G/BBB Syndrome greatly varies depending on the severity of their symptoms
- With proper treatment of symptoms, most individuals are able to lead normal lives with few problems.
Additional and Relevant Useful Information for Opitz G/BBB Syndrome:
The following DoveMed website link is a useful resource for additional information:
What are some Useful Resources for Additional Information?
National Center for Biotechnology Information (NCBI)
National Library of Medicine
8600 Rockville Pike Building 38A Bethesda, MD 20894
Phone: 1 (888) 346-3656
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126 Gaithersburg, MD 20898-8126
Toll-Free: (888) 205-2311
TTY: (888) 205-3223
International Telephone Access Number: (301) 251-4925
Fax: (301) 251-4911
References and Information Sources used for the Article:
http://ghr.nlm.nih.gov/condition/opitz-g-bbb-syndrome (accessed on September 9, 2013)
http://www.ncbi.nlm.nih.gov/books/NBK1327/ (accessed on September 9, 2013)
http://rarediseases.info.nih.gov/gard/193/opitz-gbbb-syndrome/resources/1 (accessed on September 9, 2013)
http://www.nationwidechildrens.org/opitz-g-bbb-syndrome (accessed on September 9, 2013)
http://www.wakehealth.edu/Health-Encyclopedia/Health-Topics/X-Linked-Opitz-Gbbb-Syndrome.htm?LangType=1033 (accessed on September 9, 2013)
Helpful Peer-Reviewed Medical Articles:
Robin, N. H., Opitz, J. M., & Muenke, M. (1996). Opitz G/BBB syndrome: Clinical comparisons of families linked to Xp22 and 22Q and a review of the literature. American journal of medical genetics, 62(3), 305-317.
Jacobson, Z., Glickstein, J., Hensle, T., & Marion, R. W. (1998). Further delineation of the Opitz G/BBB syndrome: report of an infant with complex congenital heart disease and bladder exstrophy, and review of the literature. American journal of medical genetics, 78(3), 294-299.
Guion‐Almeida, M. L., & Richieri‐Costa, A. (1992). CNS midline anomalies in the Opitz G/BBB syndrome: report on 12 Brazilian patients. American journal of medical genetics, 43(6), 918-928.
Quaderi, N. A., Schweiger, S., Gaudenz, K., Franco, B., Rugarli, E. I., Berger, W., ... & Marion, R. W. (1997). Opitz G/BBB syndrome, a defect of midline development, is due to mutations in a new RING finger gene on Xp22. Nature genetics, 17(3), 285.
Gaudenz, K., Roessler, E., Quaderi, N., Franco, B., Feldman, G., Gasser, D. L., ... & Muenke, M. (1998). Opitz G/BBB syndrome in Xp22: mutations in the MID1 gene cluster in the carboxy-terminal domain. The American Journal of Human Genetics, 63(3), 703-710.
Fryburg, J. S., Lin, K. Y., & Golden, W. L. (1996). Chromosome 22q11. 2 deletion in a boy with Opitz (G/BBB) syndrome. American journal of medical genetics, 62(3), 274-275.
Fontanella, B., Russolillo, G., & Meroni, G. (2008). MID1 mutations in patients with X‐linked Opitz G/BBB syndrome. Human mutation, 29(5), 584-594.
Winter, J., Lehmann, T., Suckow, V., Kijas, Z., Kulozik, A., Kalscheuer, V., ... & Ropers, H. H. (2003). Duplication of the MID1 first exon in a patient with Opitz G/BBB syndrome. Human genetics, 112(3), 249-254.
Cho, H. J., Shin, M. Y., Ahn, K. M., Lee, S. I., Kim, H. J., Ki, C. S., & Kim, J. W. (2006). X-linked Opitz G/BBB syndrome: identification of a novel mutation and prenatal diagnosis in a Korean family. Journal of Korean medical science, 21(5), 790-793.
MacDonald, M. R., Schaefer, G. B., Olney, A. H., Tamayo, M., & Frías, J. L. (1993). Brain magnetic resonance imaging findings in the Opitz G/BBB syndrome: extension of the spectrum of midline brain anomalies. American Journal of Medical Genetics Part A, 46(6), 706-711.