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

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Presentation on theme: "Achondroplasia Presentation by: Sarah Maas, Isabelle McKusick and Betty House November 16, 2005."— Presentation transcript:

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 a mutation 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 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 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

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 applications to medical schools Attended Albany Medical College Pediatric Orthopedic Surgeon Specializes in orthopedic problems of dwarfism and related disorders Greenberg Center for Skeletal Dysplasia at Johns Hopkins Married, has 2-year-old with achondroplasia

11 References: Human Growth Foundation: Hopkins Medicine; Greenberg Center: March of Dimes: Little People of America (LPA): Betty Adelson, Dwarfism: Medical and Psycosocial Aspects of Profound Short Stature (Johns Hopkins University Press, 2005) MedPage Today: Encyclopedia Brittannica Online: Dwarfs: Not a Fairy Tale; film documentary produced by the Children of Difference Foundation Johns Hopkins Magazine, April 1999, “Aiming High”


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