Fragile X Syndrome

Resident’s Name: Derek Banks Date: October 10, 2008

Syndrome: Fragile X Syndrome
Incidence: 1 in 3600 males, and 1 in 4000 to 6000 females.
Etiology: A mutation or abnormality in the X chromosome. Inheritance pattern is X linked dominant, although men having a spontaneous “premutation” (a small mutation in the X chromosome with little to no effect on phenotype) can be passed to their daughters as a premutation, which is amplified in cells that develop into eggs – leading to a mutation in either son or daughter.
Features (Craniofacial/Physical): Typical appearance for people with Fragile X is an elongated face with large or protruding ears, and prominent jaw and forehead. Other physical characteristics include flat feet, large testicles, hyperextensible fingers, and low muscle tone.
Features (Medical): Males with Fragile X are usually effected more significantly than females. Behavioral features may include hyperactivity, anxiety, ADHD, fidgeting, aggression(boys), shyness(girls), and difficulty with impulse control. About one-third of males with Fragile X have autism or related behaviors. Seizures occur in some people with Fragile X (about 15% male, 5% female).
Dental Implications: From the National Fragile X Foundation: “Routine dental care is very important for children with fragile X syndrome. They often have crowded teeth and poor brushing habits, which combine to cause problems with tooth decay. High anxiety levels and tactile defensiveness may cause visits to the dentist to be very difficult, and extensive preparation may be needed (books about going to the dentist, sitting in the chair before the actual appointment, watching a sibling or parent have his or her teeth checked). Some boys with fragile X syndrome have mitral valve prolapse, and a prophylactic antibiotic needs to be taken before dental work is done. Pediatric dentists, especially those who have worked with children with special needs, often have the special expertise needed for treatment of children with fragile X.” I took the liberty of striking through the portion about premedication for mitral valve prolapse, but, as always, the standard of care is consulting the child’s physician.
Recent Findings: None to speak of.
Miscellaneous/Summary: We will all almost certainly treat children with Fragile X. It’s good to have a bit of background.