The undiagnosed diseases are many different diseases, which is why symptoms can vary greatly.

Some of the undiagnosed children are very seriously ill right from birth or fall ill during the newborn period. They often have severe developmental and motor delays. Intractable epilepsy is common among children who have fallen ill during the first year of life. 

Others fall ill at some point during childhood or adolescence. Even in this group, children often have intractable epilepsy as well as other complex neurological symptoms. But it can be any symptom because there are many different diseases.

An undiagnosed disease can be progressive/degenerative, which means that the child gets worse and then has completely new symptoms as time passes.

Some children have an undiagnosed progressive disease, which means they are healthy when they are born or have mild symptoms that cannot be linked to any serious illness. They develop normally but after a few years, the child becomes sick without anyone understanding what kind of disease has affected the child. The disease worsens, the child gets worse and worse.

The Wilhelm Foundation works for all children who do not have a diagnosis (cause diagnosis). Are you a parent of a sick child who has no diagnosis? Read also about Wilhelm Foundation's Parent Group