Health aspects of Down syndrome

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Down syndrome is a genetic disease resulting from the presence of all or part of an extra 21st chromosome. The medical consequences of this extra genetic material are highly variable and may affect the function of any organ system or bodily process. The health aspects of Down syndrome encompass anticipating and preventing effects of the disease, recognizing complications of the disorder, managing individual symptoms, and assisting the individual and his/her family in coping and thriving with the illness.[1]

The most common manifestations of Down syndrome are the characteristic facial features, cognitive impairment, congenital heart disease, hearing deficits, short stature, and Alzheimer's disease. Other less common serious illnesses include leukemia, immune deficiencies, and epilepsy.

Down syndrome can result from several different genetic mechanisms. This results in a wide variability in individual symptoms due to complex gene and environment interactions. Prior to birth, it is not possible to predict the symptoms that an individual with Down syndrome will develop. Some problems are present at birth, such as certain heart malformations. Others become apparent over time, such as epilepsy.

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[edit] Individual symptoms

[edit] Endocrinology and hematology

Individuals with DS are at increased risk for dysfunction of the thyroid gland, an organ which helps control metabolism. Low thyroid (hypothyroidism) is most common, occurring in almost a third of those with DS. This can be due to absence of the thyroid at birth (congenital hypothyroidism) or due to attack on the thyroid by the immune system.[2] Reproduction is also affected by DS. Women with DS are less fertile and often have difficulties with miscarriage, premature birth, and difficult labor. However, women with DS are capable of having children without the extra chromosome 21 of DS.[3] Men with DS are almost uniformly infertile, exhibiting defects in spermatogenesis.[4]

Hematologic malignancies such as leukemia are more common in children with DS. In particular, the risk for acute lymphoblastic leukemia is at least 10 times more common in DS and for the megakaryoblastic form of acute myelogenous leukemia is at least 50 times more common in DS. Transient leukemia is a form of leukemia which is rare in individuals without DS but affects up to 20 percent of newborns with DS. This form of leukemia is typically benign and resolves on its own over several months, though it can lead to other serious illnesses.[5] In contrast to hematologic malignancies, solid tumor malignancies are less common in DS, possibly due to increased numbers of tumor suppressor genes contained in the extra genetic material.[6]

[edit] Gastrointestinal and growth

Down syndrome increases the risk of Hirschsprung's disease, in which the nerve cells that control the function of parts of the colon are not present.[7] This results in severe constipation. Other congenital anomalies occurring more frequently in DS include duodenal atresia, annular pancreas, and imperforate anus. Gastroesophageal reflux disease and celiac disease are also more common among people with DS.[8]

Growth parameters such as height, weight, and head circumference are smaller in children with DS than with individuals of the same age. Adults with DS tend to have short stature — the average height for men is 5 feet 1 inch (157 cm) and for women is four feet 9 inches (144 cm).[9] Individuals with DS are also at increased risk for obesity as they age.[10]

[edit] Neurology

The neurologic consequences of DS manifest early in life. Infants with Down Syndrome have a decreased muscle tone and are more flexible. Mental retardation becomes apparent as individuals with DS grow and develop — sitting, walking, and talking are typically delayed. Children and adults with DS are at increased risk for developing epilepsy.[11][12] As adults age, the risk for Alzheimer's disease increases, with more than half of individuals with DS older than 50 developing Alzheimer's disease.

[edit] Ophthalmology and otolaryngology

Eye disorders are more common in people with DS. Almost half have strabismus, in which the two eyes do not move in tandem. Refractive errors requiring glasses or contacts are also common. Cataracts (opacity of the lens) and glaucoma (increased eye pressures) are also more common in DS.[13]

Hearing loss affects more than half of individuals with DS.[14] Frequent infections of the middle ear (otitis media) and obstructive sleep apnea are also more common DS.[15] Instability of the atlanto-axial joint occurs in ~15% of people with DS and may lead to the neurologic symptoms of spinal cord compression.[16]

[edit] Prevention and screening

The American Academy of Pediatrics, among other health organizations, has issued a series of recommendations for screening individuals with Down Syndrome for particular diseases.[17] These guidelines enable health care providers to identify and prevent important aspects of DS. All other typical newborn, childhood, and adult screening and vaccination programs should also be performed.

[edit] Birth

Initial examination of newborns with DS should pay particular attention to certain physical signs which are more commonly found in DS. Evaluation of the red reflex can help identify congenital cataracts. Movement of the eyes should be observed to identify strabismus. Constipation should raise concerns for Hirschsprung's disease and feeding problems should prompt intense education to ensure adequate input and nutrition.

At birth, an ultrasound of the heart (echocardiogram) should be done immediately in order to identify congenital heart disease. A complete blood count should be done in order to identify pre-existing leukemia. A hearing test using brainsteam auditory evoked responses (BAERS) testing should be performed and any hearing deficits further characterized. The thyroid function should also be tested. Early Childhood Intervention should be involved from birth to help coordinate and plan effective strategies for learning and development.

[edit] Childhood and adulthood

As children with DS grow, their progress should be plotted on a growth chart in order to detect deviations from expected growth. Special growth charts are available so that DS children can be compared with other children with DS. Thyroid function testing should be performed at 6 months and 12 months of age as well as yearly thereafter. Evaluation of the ears for infection as well as objective hearing tests should be performed at every visit. Formal evaluation for refractive errors requiring glasses should be performed at least every two years with subjective vision assessments with each visit. After the age of three, an x-ray of the neck should be obtained to screen for atlanto-axial instability. As the child ages, yearly symptom screening for obstructive sleep apnea should be performed.[17]

[edit] Treatment

Treatment of individuals with Down Syndrome depends on the particular manifestations of the disease. For instance, individuals with congenital heart disease may need to undergo major corrective surgery soon after birth. Other individuals may have relatively minor health problems requiring no therapy.

[edit] Plastic surgery

Plastic surgery has sometimes been advocated and performed on children with Down syndrome, based on the assumption that surgery can reduce the facial features associated with Down syndrome, therefore decreasing social stigma, and leading to a better quality of life.[18] Plastic surgery on children with Down syndrome is uncommon,[19] and continues to be controversial. Researchers have found that for facial reconstruction, "...although most patients reported improvements in their child's speech and appearance, independent raters could not readily discern improvement...."[20] For partial glossectomy (tongue reduction), one researcher found that 1 out of 3 patients "achieved oral competence," with 2 out of 3 showing speech improvement.[21] Len Leshin, physician and author of the ds-health website, has stated, "Despite being in use for over twenty years, there is still not a lot of solid evidence in favor of the use of plastic surgery in children with Down syndrome."[22] The National Down Syndrome Society has issued a "Position Statement on Cosmetic Surgery for Children with Down Syndrome"[23] which states that "The goal of inclusion and acceptance is mutual respect based on who we are as individuals, not how we look."

[edit] Alternative treatment

The Institutes for The Achievement of Human Potential is a non-profit organization which treats children who have, as the IAHP terms it, "some form of brain injury," including children with Down syndrome. The approach of "Psychomotor Patterning" is not proven,[24] and is considered alternative medicine.

[edit] Lifespan

These factors contribute to a significantly shorter lifespan for people with Down syndrome. One study, carried out in the United States, shows an average lifespan of 49 years.[25]

[edit] References

  1. ^ American Academy of Pediatrics. Committee on Genetics. American Academy of Pediatrics: Health supervision for children with Down syndrome. Pediatrics. 2001 Feb;107(2):442-9. PMID 11158488
  2. ^ Karlsson B, Gustafsson J, Hedov G, Ivarsson SA, Anneren G. Thyroid dysfunction in Down's syndrome: relation to age and thyroid autoimmunity. Arch Dis Child. 1998 Sep;79(3):242-5. PMID 9875020
  3. ^ Bovicelli L, Orsini LF, Rizzo N, Montacuti V, Bacchetta M. Reproduction in Down syndrome. Obstet Gynecol. 1982 Jun;59(6 Suppl):13S-7S. PMID 6211644
  4. ^ Johannisson R, Gropp A, Winking H, Coerdt W, Rehder H, Schwinger E. Down's syndrome in the male. Reproductive pathology and meiotic studies. Hum Genet. 1983;63(2):132-8. PMID 6220959
  5. ^ Transient leukaemia--a benign form of leukaemia in newborn infants with trisomy 21. Br J Haematol. 2003 Mar;120(6):930-8. Review. PMID 12648061
  6. ^ Hasle H, Clemmensen IH, Mikkelsen M. Risks of leukaemia and solid tumours in individuals with Down's syndrome. Lancet. 2000 Jan 15;355(9199):165-9. PMID 10675114
  7. ^ Ikeda K, Goto S. Additional anomalies in Hirschsprung's disease: an analysis based on the nationwide survey in Japan. Z Kinderchir. 1986 Oct;41(5):279-81. PMID 2947399
  8. ^ Zachor DA, Mroczek-Musulman E, Brown P. Prevalence of celiac disease in Down syndrome in the United States. J Pediatr Gastroenterol Nutr. 2000 Sep;31(3):275-9. PMID 10997372
  9. ^ Cronk C, Crocker AC, Pueschel SM, Shea AM, Zackai E, Pickens G, Reed RB.Growth charts for children with Down syndrome: 1 month to 18 years of age. Pediatrics. 1988 Jan;81(1):102-10. PMID 2962062
  10. ^ Rubin SS, Rimmer JH, Chicoine B, Braddock D, McGuire DE. Overweight prevalence in persons with Down syndrome. Ment Retard. 1998 Jun;36(3):175-81. PMID 9638037
  11. ^ Goldberg-Stern H, Strawsburg RH, Patterson B, Hickey F, Bare M, Gadoth N, Degrauw TJ.Seizure frequency and characteristics in children with Down syndrome. Brain Dev. 2001 Oct;23(6):375-8. PMID 11578846
  12. ^ Menendez M. Down syndrome, Alzheimer's disease and seizures. Brain Dev. 2005 Jun;27(4):246-52. Review. PMID 15862185
  13. ^ Caputo AR, Wagner RS, Reynolds DR, Guo SQ, Goel AK. Down syndrome. Clinical review of ocular features. Clin Pediatr (Phila). 1989 Aug;28(8):355-8. PMID 2527102
  14. ^ Roizen NJ, Wolters C, Nicol T, Blondis TA. Hearing loss in children with Down syndrome. J Pediatr. 1993 Jul;123(1):S9-12. PMID 8320600
  15. ^ Clarke RW. Ear, nose and throat problems in children with Down syndrome. Br J Hosp Med (Lond). 2005 Sep;66(9):504-6. Review. PMID 16200785
  16. ^ Pueschel SM, Scola FH. Atlantoaxial instability in individuals with Down syndrome: epidemiologic, radiographic, and clinical studies. Pediatrics. 1987 Oct;80(4):555-60. PMID 2958770
  17. ^ a b American Academy of Pediatrics Committee on Genetics. (2001) Health Supervision for Children With Down Syndrome. Pediatrics 107(2):442-449. Online at Health Supervision for Children With Down Syndrome. Accessed 13 August 2006
  18. ^ Olbrisch RR (1982). "Plastic surgical management of children with Down syndrome: indications and results". British Journal of Plastic Surgery 35: 195-200.
  19. ^ Parens, E. (editor) (2006). Surgically Shaping Children : Technology, Ethics, and the Pursuit of Normality. Baltimore: Johns Hopkins University Press. ISBN 0-8018-8305-9.
  20. ^ Klaiman, P and E Arndt (1989). "Facial reconstruction in Down syndrome: perceptions of the results by parents and normal adolescents". Cleft Palate Journal 26: 186-190; discussion 190-192. PMID 2527096. Also, see Arndt, EM, A Lefebvre, F Travis, and IR Munro (1986). "Fact and fantasy: psychosocial consequences of facial surgery in 24 Down syndrome children". Br J Plast Surg 4: 498-504. PMID 2946342.
  21. ^ SA Pensler (1990). "The efficacy of tongue resection in treatment of symptomatic macroglossia in the child". Ann Plast Surg 25: 14-17.See also KM Van Lierde, H Vermeersch, J Van Borsel, P Van Cauwenberge (2002/2003). "The impact of a partial glossectomy on articulation and speech intelligibility". Oto-Rhino-Laryngologia Nova 12: 305-310.
  22. ^ Leshin, L (2000). Plastic Surgery in Children with Down Syndrome. Retrieved on 2006-07-25.
  23. ^ National Down Syndrome Society. Position Statement on Cosmetic Surgery for Children with Down Syndrome. Retrieved on 2006-06-02.
  24. ^ For criticism of the method, see Novella, S. Psychomotor Patterning. Retrieved on 2006-06-02.
  25. ^ Young, Emma. "Down's syndrome lifespan doubles", New Scientist, 2002-03-22. Retrieved on 2006-10-14.

[edit] See also

Down syndrome

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