About Lenz Microphthalmia
The New York Center for Rare Diseases supports the mission and guidelines of the Genetic and Rare Diseases Information Center (GARD). The following information is provided by the NIH.
Summary
Lenz microphthalmia syndrome is one of a group of genetic disorders known as syndromic microphthalmia. These conditions involve abnormal development of the eyes and several other parts of the body. Eye symptoms may include underdeveloped (small) or absent eyes, clouding of the lens (cataracts), uncontrolled eye movements (nystagmus), a gap or split in structures that make up the eye (coloboma), and glaucoma. These symptoms may affect one or both eyes and may cause vision loss or blindness. Other signs and symptoms may include abnormalities of the ears, teeth, hands, skeleton, urinary system, brain, and heart. Around 60% of people with this condition have delayed development or intellectual disability ranging from mild to severe. There are at least 10 different types of syndromic microphthalmia that are caused by genetic changes in different genes. Most cases of Lenz microphthalmia are caused by genetic changes of the BCOR gene and are inherited in an X-linked recessive pattern. Other forms of syndromic microphthalmia are inherited in different patterns depending on the gene involved.
Causes
What Causes This Disease?
Genetic Mutations: Microphthalmia, Lenz type is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.
If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.
Known Genetic Mutations: Microphthalmia, Lenz type is caused by genetic mutations in the following known gene(s):
BCOR, NAA10
Given these known genetic mutation(s), you may want to ask your health care team if genetic testing is right for you. Genetic tests are laboratory tests that use samples of blood, saliva, or other tissues to help identify changes in genes, chromosomes, or proteins. Genetic testing can help confirm or rule out a suspected genetic disease, or can provide other useful information to your health care team.
Can This Disease Be Passed Down From Parent to Child?
Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.
There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):
X-Linked: X-linked inheritance means the genetic mutation is located on the X chromosome, one of the sex chromosomes. The male sex chromosome pair consists of one X and one Y chromosome (XY). The female sex chromosome pair consists of two X chromosomes (XX). Because males have just one X chromosome, it takes only one copy of the mutated gene to cause the disease. Females that have one copy of the mutated gene may have symptoms similar to those experienced by affected males, but usually have less severe symptoms, or no symptoms at all.
Female parents with one X-linked mutated gene have a 50% chance of passing on the mutation to each of their biological children. Male parents with an X-linked mutated gene will pass on the mutation to all their female children but cannot pass the mutation on to their male children.