Lesser Known Disorders
Each issue of this series contains at least three lesser known disorders. Some of these disorders may contain subtypes which will also be presented. You will also notice that each disorder has a code. These codes represent the coding system for all disabilities and disorders listed in the Educator’s Diagnostic Manual(EDM) Wiley Publications.
Disorders in this issue:
LD 10.03-Tactile Sensory Integration Disorder
Disability Category: Learning Disability
Definition
A type of sensory integration disorder specifically associated with difficulties in judging the appropriate amount of pressure needed to perform motor acts (Learning Disabilities Association, 2005).
Explanation
Children with Tactile Pressure Sensory Integration Disorder have trouble judging the right amount of pressure needed to perform motor acts. Examples of tactile pressure include holding an egg in two fingers without breaking or dropping it, tapping someone playfully rather than hitting him/her, strumming a guitar softly, and pushing an elevator button with the right amount of pressure.
OI 1.01-Fibrous Dysplasia
Disability Category-Orthopedic Impairment
Definition
Fibrous dysplasia is a chronic disorder in which bone expands due to abnormal development of fibrous tissue, often resulting in one, or more, of the following:
- uneven growth of bones
- pain
- brittle bones
- bone deformity (University of Maryland Medical System 2003)
Some patients have only one bone affected (monostotic), whereas other patients have numerous bones affected (polyostotic) (NIH Osteoporosis and Related Bone Diseases, 2000).
Explanation
The following are the most common symptoms for fibrous dysplasia. However, each individual may experience symptoms differently. Symptoms may include:
- a waddling walk
- bone pain (as a consequence of the expanding fibrous tissue in the bone)
- bone deformity
- bone pain
- bone fractures
- scoliosis—a lateral, or sideways, curvature and rotation of the back bones (vertebrae), giving the appearance that the person is leaning to one side.
The symptoms of fibrous dysplasia may resemble other bone disorders or medical problems. Always consult your physician for a diagnosis (U.S. National Library of Medicine, 2003a; University of Maryland Medical Center, 2003).
VI 2.01 Bietti’s Crystalline Dystrophy
Disability Category: Visual Impairment
Definition
Bietti’s crystalline dystrophy (BCD) is an inherited eye disease. (National Eye Institute, 2005e).
Explanation
Bietti’s crystalline dystrophy (BCD) named for Dr. G. B. Bietti, an Italian ophthalmologist, who described three patients with similar symptoms in 1937. The symptoms of BCD include: crystals in the cornea (the clear covering of the eye); yellow, shiny deposits on the retina; and progressive atrophy of the retina, choriocapillaries and choroid (the back layers of the eye). This tends to lead to progressive night blindness and visual field constriction. BCD is a rare disease and appears to be more common in people with Asian ancestry.
People with BCD have crystals in some of their white blood cells (lymphocytes) that can be seen by using an electron microscope. Researchers have been unable to determine exactly what substance makes up these crystalline deposits. Their presence does not appear to harm the patient in any other way except to affect vision.
From family studies, we know that BCD is inherited primarily in an autosomal recessive fashion. This means that an affected person receives one nonworking gene from each of his or her parents. A person who inherits a nonworking gene from only one parent will be a carrier, but will not develop the disease. A person with BCD syndrome will pass on one gene to each of his or her children. However, unless the person has children with another carrier of BCD genes, the individual’s children are not at risk for developing the disease (National Eye Institute, 2005e).
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