There are two main types of birth defects: structural and functional/ developmental.
- Nervous system or brain problems - such as learning disabilities, intellectual and developmental disabilities, behavioral disorders, speech or language difficulties, convulsions, and movement trouble. Some examples of birth defects that affect the nervous system include Autism, Down syndrome, Prader-Willi syndrome, and Fragile X syndrome.
- Sensory problems - such as blindness, cataracts and other visual problems, and varying degrees of hearing loss including deafness
- Metabolic disorders - involve a body process or chemical pathway or reaction, such as conditions that limit the body's ability to get rid of waste materials or harmful chemicals. Two common metabolic disorders are phenylketonuria (PKU) and hypothryroidsim.
- Degenerative disorders - are conditions that might not be obvious at birth, but cause one or more aspects of health to steadily get worse. For example, X-linked adrenoleukody...

