Question: I am a 29 year old female, and have family history of HCM in uncles and some cousins on father's side. However, my father who is 57 years old got tested recently and has no sign of HCM, myself also no sign, my sister 18 years old also no sign and my brother 27 also no HCM.
However, my brother's first echo which was done by a qualified tech and not cardiologist mentioned no LVH (0.8cm ivsd) but sigmoid shaped septum. The doctor dismissed this and did not see the echo picture just read the report and said normal. However i was worried as i read sigmoid septum is found mainly in elderly people. So took him for a follow up echo after one year, this time done by cardiologist. The doctor did echo and said he cannot call it sigmoid septum and it is a normal variant and normal septum. I have attached a 2D four chamber echo which shows the septum and he measures even the thickest part the one that looks like a bulge and it was normal (1.1cm), m mode showed IVSd as 0.8cm. Can you please take a look at the echo and suggest in your experience and opinion if this is a normal looking septum or sigmoid ?
My brother is a smoker and body builder who goes to the gym on a daily basis but no steroids. Healthy diet.

Thank you so much for the reponse. So what looks like a slight bulge in the middle of the septum is not considered sigmoid ? Is there a cause for this bulge or would a normal septum look like this ?
the bulge measured at 1.1cm and the doctor also measured the based just below the bulge in front of me and it was 0.8-0.9cm is it normal to have different thicknesses like this ?

I read that myocardial disarray is usually seen in patients who have HCM or are gene positive but no LVH. We have not had genetic testing so we don't know of my father or brother carry the gene. Would this bulge be caused by subtle myocardial disarray by any chance ? Or is that not relevant here?
In such people, would one assume an unknown cause for this IVS shape or consider it normal anatomy ?