cystic hygoma

hi 21 years ago i gave birth to a boy which had a large cystic hygroma ,he was opperated as it grew so large in 2 das that it obstructed his air ways which caused a cardiac arest,all his life he has spent alot of his life in an out of gt ormond st hospital as he had to have a traceostomy after the opp he has now been with out it for about 8 years,my 1st son was born healthy and is 26 his partner is 12 weeks pregnant and the scan has showed something is wrong with the babies neck and it could be a cystic hygroma im very worried about this knowing what i went through with my other son,could you tell me why this has came out again in my normal childs baby as i have lots off unaswered qestions, i also have another normal son who is 23 could it also efect a child off his.
                                        thanks.

[AnnieBrooke]

I don't know very much about cystic hygroma, but here is some information from the web:

Cystic hygromas aren't usually inherited so they aren't genetic in that sense. Most cases (60-80%) are caused by problems with chromosomes and not single genes. These chromosomal abnormalities are problems that happen during egg or sperm production and are generally random; not something that runs in families. As a mother gets older, these types of chromosomal problems increase (Down syndrome is the classic example). This may make having another baby with a cystic hygroma more likely.

Cystic hygromas are pretty rare, they occur in 1:4,000 pregnancies. A cystic hygroma is a thin-walled sac commonly found in the head and neck area that often looks like a soft bulge under the skin. Cystic hygromas are filled with lymph which is the fluid that travels in the lymphatic system of the body. Cystic hygromas occur when the lymph vessels that make up the lymphatic system aren't formed properly.

Most babies or fetuses with cystic hygromas have some kind of chromosomal abnormality. What this usually means is they are missing or have an extra chromosome. For example, cystic hygromas are pretty common in Turner's syndrome, a condition in which one of the two X chromosomes is missing.

The other causes of cystic hygroma are less common. Cystic hygromas can happen with diseases like Noonan's syndrome. Noonan's can run in families, but it usually happens randomly. Cystic hygromas can also be caused by viral infections or alcohol use by the mother during pregnancy, although this is rare. Finally, cystic hygromas can occur from an unknown cause.