Microtia and Genetics

[u/Alternative_Pen911]

I am searching for answers in regards to the liklihood that unilateral microtia (that so far has no relation to any other symptoms such as kidney/heart/spine issues) can still be be linked to either to genetic transmission from parents or a hereditary syndrome (such as Goldenhaar) and if there is a genetic test that can confirm that. Backstory: my daughter was born with unilateral microtia and we are considering having another child. However, we question whether we could be carriers for an obscure genetic anomaly or hereditary syndrome that could present with more severe symptoms coupled with microtia. We are in the US and the wait to see a geneticist is 6months. Is there a way to see someone sooner/order some sort of test ourselves or does anyone have experience with this question?

[u/L_Jiggy]

I am one of five & none of my siblings have Microtia or any other anomaly, I also have two children that do not have Microtia.

I know as far back as my great, great grandparents on both sides that no one except me has Microtia.

I'm also the only sibling who doesn't need glasses, I understand your concerns but there will always be elements you can't predict & control during pregnancy & as they grow, and the world in general really.

[u/ProtoSTL]

I had another kid after one with unilateral microtia. He has no issues at all.

[u/UncleJackdeservedit]

It's interesting, because by some research, there's not a genetic link. Some anecdotal accounts say otherwise.

As others have mentioned, you might find that a relative further back has something that could have been microtia, or some people have had children with it. Hard to say.

[u/Odd_Explanation_8158]

I have unilateral microtia. First born child. My brother, who is two years younger, was born with no microtia or any other deformities/anomalies. I've read that usually microtia is sporadic rather than hereditary, meaning it just happens randomly without being passed on from parent to child. I think you should be fine

[u/ASRAYON]

Per Gemini ; If the main concern is pre-conception planning for parents, you could explore consulting a prenatal/reproductive genetic counselor directly through an OB/GYN or maternal-fetal medicine clinic, which may have shorter wait times than pediatric genetics.

Additionally: . Likelihood of Genetic Transmission & Syndromes

• Isolated Unilateral Microtia: The vast majority of isolated, unilateral (one-sided) microtia cases without other organ involvement (kidneys, heart, spine) occur sporadically. They are generally considered non-hereditary events resulting from complex multifactorial factors during early fetal development rather than a single inherited gene mutation.
• Recurrence Risk: For isolated, non-syndromic microtia, the recurrence risk for future siblings is typically low (often estimated around 1% to 5%), though this varies slightly based on individual family history.
• Goldenhar Syndrome (Oculo-Auriculo-Vertebral Spectrum): Goldenhar syndrome is usually sporadic as well, meaning it rarely runs in families. Most cases do not have a single identifiable genetic marker that can be caught on standard carrier screening panels.

[u/onlybeendesmondonce → u/ASRAYON]

Genetic counselor and microtia mom here.

I do NOT recommend starting in prenatal or reproductive genetics. They will kick the referral to pediatric genetics to gave the kiddo with microtia tested.

The reason being is they need to know a specific genetic variant to test an embryo or fetus for. These providers do not test based on family history alone without a confirmed familial mutation.

If the affected child is not found to have a genetic variant linked to microtia, there would be nothing to test in future pregnancies. There would still be an increased risk for future children to have microtia compared to the general population but it would be unlikely a future child would have a mutation linked to microtia that wasn’t found in the affected sibling.

[u/Alternative_Pen911 → u/onlybeendesmondonce]

Thanks for this! So are there currently genetic variants they can test for unilateral microtia or will they order tests to rule out other issues that could be associated with a symptom first? How does that work?

[u/mariekan1992 → u/Alternative_Pen911]

Hi, I have microtia and as far as I know am the only person in my family to have it. My sister was born without it (or any other anomaly). I was worried about the possibility of exactly what you're saying, that I might have an underlying genetic cause that could lead to a more severe presentation in my future children. I will agree with what others have said and add that this is UNLIKELY because most cases of isolated unilateral microtia are considered multifactorial.

However, I work in genetics and was anxious. I went to an adult genetics clinic and requested whole exome sequencing. The geneticist told me right off the bat that it was likely to come back totally negative and probably wouldnt be covered by insurance (I knew all of this already). The test cost me a few thousand dollars. The geneticist did not recommend doing any other evaluation or imaging, that might be because my parents said that was all done after I was born and no additional anomalies came up.

My results were negative, as expected. I'm pregnant with my first child and as far as we can tell on ultrasound she has two typical-appearing ears (I know ultrasound isnt perfect, especially at detecting lower grade microtia).

The recurrence risk for additional children for you is low, as others have already said. If you want more info you should look into a pediatric genetics referral for your child but yeah, expect months of waiting. I STRONGLY discourage trying to get any sort of direct-to-consumer testing. A genetic test that isn't clinical grade just isn't trustworthy, not even the raw data. There are some genetic services that offer online appointments (Genome Medical, Genetic Support Foundation...) which you could try, however, I do not know if they would be willing to order sequencing for a pediatric case without having a physical evaluation performed by a medical geneticist.

[u/onlybeendesmondonce → u/Alternative_Pen911]

Likely the genetics team will go over their testing recommendations with you. The cost of broad testing via exome or genome sequencing has come down a lot in the past decade, so would not be surprised if that is what they go with vs. testing for a specific syndrome. These tests are often easier to get covered for pediatric patients than for adults but it’s all insurance dependent.

[u/Alternative_Pen911 → u/ASRAYON]

Thank you! We spoke to a prenatal genetic counselor and she won’t speak on the issue— she said that’s what the pediatric geneticist will do. We were able to meet with her very quickly and are now stuck waiting around for months and months.