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Achondroplasia

Achondroplasia. Presentation by: Sarah Maas, Isabelle McKusick and Betty House November 16, 2005. What is Achondroplasia? . Achondroplasia is an autosomal dominant condition It was discovered in 1994 by Dr. John Wasmuth

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Achondroplasia

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  1. Achondroplasia Presentation by: Sarah Maas, Isabelle McKusick and Betty House November 16, 2005

  2. What is Achondroplasia? • Achondroplasia is an autosomal dominant condition • It was discovered in 1994 by Dr. John Wasmuth • It is caused by amutation of the fibroblast growth factor receptor-3 (FGFR3) gene on chromosome 4. • Achondroplasia is the most common form of Dwarfism • Although there are over 200 types of dwarfism, two-thirds have achondroplasia • It affects 1 in 25,000 • 30,000 to 50,000 in U.S. have some form of Dwarfism • It occurs in both sexes and all races • Motor skills are temporarily delayed • Cognitive skills/intelligence levels are not affected

  3. Characteristics • Characteristic features are evident at birth • Head is large, forehead is prominent • Hydrocephalus (excess fluid on the brain) may present • Protruding jaw, poor dental structure, crowded teeth • Disproportionate features • Upper extremities are shorter than lower extremities • Hands are short; fingers are stubby • Average adult height is about 4 feet tall

  4. A Social History of Achondroplasia • Depicted in ancient Egyptian art • Classical Greece and Rome • In Renaissance and Medieval courts, dwarves were often ‘owned’ as a sign of wealth • Isabella d’Este and Diego Velázquez • Scandinavian Mythology • 18th and 19th century Russia

  5. Dwarfism in 19th and 20th Century • P.T. Barnum and Charles Stratton • Effects of Hollywood

  6. Achondroplasia Today • Please don’t use the “M” word. • Acceptable terms are Dwarf or Little Person • “Dwarf tossing” is outlawed in many states • If nurtured properly, dwarf children achieve success and happiness • Us and Them: focus on similarities and ways to even out the balance • Simple, helpful tools include: • A step stool • Pedal extensions in automobiles • Tailored clothing • Support groups such as Little People’s Association

  7. Interesting hereditary facts • Nine of 10 born with achondroplasia have average-sized parents • So 90% are caused by new mutation from average-sized parents • Fathers 40+ are more likely to have children with achondroplasia • In 10%, the mutation may pass from generation to generation • If both parents have achondroplasia, their children have: • 50% chance of having achondroplasia • 25% chance of being average size • 25% chance of having two altered copies of the mutation (double-dominant or homozygous). • Homozygous infants are stillborn or die shortly after birth • Currently, there is no routine screening for achondroplasia • Couples at risk (one or both parents with achondroplasia) may choose ultrasound and DNA testing for achondroplasia or double-dominant/homozygous

  8. How does Achondroplasia affect development? • Obstructive Upper Airway Disease • Middle-ear infections; hearing problems • Because of large heads, short limbs and poor muscle tone, motor skills are delayed • Spinal alignment problems • Back pain • Walking problems • Excessive weight gain

  9. Treatment Options • Growth Hormone Therapy (GHT) • Lumbar lordosis (reverse curvature of spine) • Lumbosacral spinal stenosis (narrow spinal canal adds pressure to spinal cord) • Lumbar laminectomy surgery • Limb lengthening surgery is very controversial: • 70% have transient pain • 45% have infections • 35% experience foot drop • 30% experience stiff knees • 15% experience stiff ankles • Reports of incorrect alignment (legs are uneven)

  10. Personal Account • Dr. Michael Ain • Sent out 20-30 applications to medical schools • Attended Albany Medical College • Pediatric Orthopedic Surgeon • Specializes in orthopedic problems of dwarfismand related disorders • Greenberg Center for Skeletal Dysplasia at Johns Hopkins • Married, has 2-year-old with achondroplasia

  11. References: Human Growth Foundation: http://home.earthlink.net/~dkennedy56/dwarfism_hgfachon.html Hopkins Medicine; Greenberg Center: http://www.hopkinsmedicine.org/greenbergcenter/achon.htm March of Dimes: http://www.marchofdimes.com/professionals/681_1204.asp Little People of America (LPA): http://www.lpaonline.org/around.html Betty Adelson, Dwarfism: Medical and Psycosocial Aspects of Profound Short Stature (Johns Hopkins University Press, 2005) MedPage Today: http://www.medpagetoday.com/OBGYN/Pregnancy/tb/1749 Encyclopedia Brittannica Online: http://www.britannica.com/eb/article-9031649?query=dwarfism%20history&ct= Dwarfs: Not a Fairy Tale; film documentary produced by the Children of Difference Foundation Johns Hopkins Magazine, April 1999, “Aiming High” http://www.jhu.edu/~jhumag/0499web/ortho.html

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