There are a number of other conditions that can occur as a result of BWS. I'm not going to attempt to list them all, just some of the ones we have to be most concerned about.
Hypotonia/ developmental delays - Hypotonia (reduced muscle tone) is a symptom of many different genetic syndromes, including BWS. Many kids have developmental delays as a result of the hypotonia. We have no idea if Micaelyn had any early developmental delays since we didn't get her until she was 3 1/2. It's quite possible she had some early delays but had mostly caught up by the time we got her. Elianna did have some delays but not severe. She was later to roll over than expected, later to sit up, later to walk, etc., but her delays were not so severe as to cause any great concern. I knew to expect some delays, so we just gave her a lot of extra help. All her older siblings have been great at encouraging her, and they provide a lot of motivation for her to keep trying new things because she is so eager to keep up with them.
Hyperactivity/ stubbornness/ aggressiveness/ other difficult behaviors - It's hard to know how much of a young child's difficult behavior is normal immaturity combined with personality versus how much of it is a result of an abnormal disorder. Nonetheless difficult behaviors are another concern with BWS. Truthfully neither of our girls with BWS could be considered an "easy" child. Micaelyn is very sweet and loving but still requires a lot of discipline to keep her in control. Likewise, Elianna can be rather difficult at times. She and Hannah are both 2 years old but she is FAR more difficult. At the last appointment with the geneticist she was asking about Elianna's behaviors, and while Hannah was acting like a normal 2 year old Elianna was proving just how "wild" she could be. I am sometimes shocked by the aggressiveness both Elianna and Micaelyn show at times. Elianna can be particularly rough with Hannah, and Micaelyn can be downright awful towards Malachi at times for no reason. Both girls are extra active, stubborn, very strong-willed, and constantly pushing the limits with their behaviors.
Seizures - Seizures are another risk associated with BWS. Neither Elianna nor Micaelyn have had a seizure that we know of (we can't know for sure about Micaelyn since she was older at adoption). However, because I know they are at risk for them I am always extra careful at keeping temperatures under control when they are sick (Elianna has had many episodes of high fever). One seizure is concerning enough, but I also think about the possibility of a febrile seizure leading to a recurring seizure problem.
Kidney problems - People with BWS are at higher risk for a number of different kidney problems. Our girls get regular ultrasounds and kidney function tests to screen for kidney problems. We have had extra concern about Micaelyn since the formula she drank in China was tainted with melamine, but so far she hasn't had any problems.
Cardiac abnormalities - Cardiac abnormalities are another concern with BWS. So far we haven't had any concerns with Micaelyn. It was recommended to us by the geneticist she be evaluated at some point by a cardiologist, but since she has no signs or symptoms we have decided to wait until she is old enough to participate in sports and have the cardiologist evaluate her at that time. Elianna was born with a murmur, probably caused by a "hole in the heart" type defect. She was referred to a cardiologist before we adopted her, but she never got seen. By the time we got her the doctor here didn't feel there was a reason for concern, and her murmur is no longer audible so most likely she was born with a heart defect that corrected itself. Once she is older and participating in sports we will have her evaluated by a cardiologist just to make sure there are no more cardiac abnormalities. There is always the risk the girls could be fine and then develop abnormalities later such as cardiomegaly (an enlarged heart), so by holding off the cardiac testing until they are older we can catch any issues that arise while they are growing (the risk for heart problems isn't high enough for repeated testing each year). Obviously if they were to start having any signs or symptoms of cardiac problems we would get them tested immediately.
Teeth problems - Although there are several problems with the teeth related to an enlarged tongue (e.g. underbite, teeth splaying), I've read there can also be a problem with the enamel on the teeth. At her most recent dental exam the dentist said Micaelyn was starting to develop places on many of her teeth where the enamel was wearing away. He referred us to another dentist who will help us determine the best course of treatment.
Frequent Illnesses - Kids with genetic disorders typically have weaker immune systems and deal with more illnesses than other kids. It seems likely this is the case with both Elianna and Micaelyn. They both get sick more often than the rest of their siblings and take longer to recover from illness. It seems like Elianna especially deals with an excessive amount of sickness, and although she and Hannah are constantly together and always sharing drinks, pacifiers, spoons, etc. Hannah doesn't deal with near the sickness Elianna does. Likewise, Micaelyn deals with far more sickness than Malachi and Caleb with whom she goes to the same school, and also despite the fact she frequently shares drinks and food with Malachi.
Here is an image I got from a BWS group that lists some of the features of BWS. There are certainly many features not listed, and I have no idea what the source of the image is but thought it was quite interesting.
