That's a good question. The name literally means "a harmless case of poor muscle tone (strength, elasticity) since birth". It is a descriptive label for any congenital disease whose main symptoms are weak and floppy muscles. "Benign congenital hypotonia" is often inaccurately used as if it were a proper disease in its own right. If this is the only diagnosis given, it is not really a diagnosis, but a label for "we don't know".
BCH is normally discovered within the first few months of life. Or rather, symptoms are noticed within a few weeks to a year (sometimes with a provisional label of "failure to thrive"), and then months are spent ruling out everything else, and then perhaps a label of "Benign Congenital Hypotonia" (or some variation thereupon) is given, with no real answers. As my mother puts it, either I have Werdnig-Hoffman's disease or Benign Congenital Hypotonia, but since I'm still alive, I have BCH.
A diagnosis of BCH is sometimes considered a form of muscular dystrophy or cerebral palsy, depending on the symptoms and the doctor. If the cause of the hypotonia is thought to lie in the brain, then it might be classified as a cerebral palsy. If the cause seems to be in the muscles, it might be classified as a muscular dystrophy, even though most forms of BCH are not seriously distrophic. If the cause is thought to be in the nerves, it could be classified as either or neither. In any case, BCH is rarely an actual muscular dystrophy or cerebral palsy, and is often not classified as either one, or anything at all for that matter.
Many forms of BCH are also associated with skeletal abnormalities.
Since BCH is a diagnosis of exclusion, people who wind up at this web site often have a scattering of other symptoms which may or may not be related. These other symptoms have included breathing problems, hypersensitivity, learning problems, fine motor or balance problems (ataxia) and more.
The outcome in any particular case depends largely on the nature of the underlying disease. Typically the hypotonia does not get much worse, and sometimes improves. Usually, life expectancy is not seriously threatened, though this is unclear to me. Hypotonia does not intrinsically affect intelligence, though a number of underlying diseases may have adverse affects on one or more aspects of cognition.
There is currently no known treatment or cure for most (or perhaps all) causes of BCH. Physical, occupational, and speech therapies are often recommended and used, with very good results. Ankle/foot orthoses are sometimes used for weak ankle muscles. Hypotonic, passive babies may need extra stimulation. Toddlers and children with speech difficulties may benefit greatly by using sign language within the family until speech has become intelligible by the family.
I don't know. Diagnosis of "BCH" is considered rare. Of people served by the Muscular Dystrophy Association, it seems on the order of one out of a thousand are diagnosed with "BCH". It affects both males and females.
Click here for one of the few other pages on the internet that describe Benign Congenital Hypotonia!
Since I have never met (in person) anyone else with this condition, nor have I had doctors take much of a look at it since I was first diagnosed as a baby, nor am I otherwise any real expert on this, I'm reluctant to generalize or make assertions about Benign Congenital Hypotonia. Most of my real understanding of this condition comes from observing my own body. It affects all of my skeletal and/or voluntary muscles, but not my heart or lungs. As a child I had all the abilities of a contortionist, though as an adult my stronger muscles (like my hamstrings) can no longer do extraordinary things. My vision is good, but not quite perfect, perhaps due to weakness of whatever muscles I use to focus with. My speech is slightly slurred. My reflexes are a bit slow, but I type very fast and can play all but the most twitchy video games quite well (meaning, I have ordinary muscle control). I could go into even smaller details, but really I am otherwise in very good health.
The practical effects on my life have been primarily social, through the reactions of others to my "hidden" disability. It rules out jobs involving heavy muscle work or standing on my feet all day. I don't know if my health insurance provider knows anything about this. I'd just as soon they didn't, as they'll take any excuse to not cover people.