Endocrinology Book

http://www.fpnotebook.com/

Klinefelter Syndrome

Aka: Klinefelter Syndrome
Advertisement
  1. Epidemiology
    1. Most common major sexual differentiation abnormality
    2. Incidence of Klinefelter Syndrome in specific cohorts
      1. Newborn males: 1 in 500 to 1000
      2. Male Breast Cancer: 7.5%
      3. Infertile males: 3%
      4. Mild Mental Retardation: 1%
  2. Pathophysiology
    1. Results in testicular dysgenesis
    2. Chromosomal abnormality with 47,XXY karyotype
      1. Abnormality of nondisjunction during meiosis
      2. Maternal or paternal origin
      3. Most of additional X Chromosome is inactivated
        1. Functioning extra genes confer phenotype
        2. More severe cases with XXXY, XXXXY or XXYY
        3. Less severe cases with mosaicism (>1 cell line)
  3. Signs
    1. Late Eunuchoid body proportions
      1. Tall, slim and underweight
      2. Long legs and short torso
      3. Obesity and varicosities may occur in 33% of patients
    2. Hypergonadotropic Hypogonadism
      1. Testes small and firm (usually <2.0 cm or 2 ml)
      2. Penis small
      3. Azoospermia or oligospermia (and Infertility)
    3. Other signs of Hypoandrogenism
      1. Gynecomastia (bilateral and painless)
      2. Decreased facial hair, but pubic hair abundant
  4. Labs
    1. Karyotype: XXY
    2. Post-Puberty labs
      1. Follicle Stimulating Hormone (FSH) increased
      2. Leutinizing Hormone (LH) increased
      3. Inhibin B decreased
      4. Increased estradiol to testosterone ratio
  5. Associated Conditions
    1. Mild Mental Retardation
      1. Motor function delay
      2. Language comprehension problems
      3. Speech may also be affected
    2. Learning Disorders
      1. Attention Deficit Disorder
      2. Dyslexia
    3. Social maladjustment
    4. Mental illness
    5. Thyroid dysfunction
    6. Diabetes Mellitus
    7. Lung disease
    8. Breast Cancer (20x risk of healthy men)
    9. Osteoporosis
  6. Management: General
    1. Complete neurodevelopment evaluation at diagnosis
      1. Indicated if diagnosis in childhood
    2. Breast Cancer surveillance
  7. Management: Testosterone Replacement after age 11
    1. Start
      1. Long acting Testosterone 25-50 mg IM q3-4 weeks
      2. Increase Testosterone dose by 50 mg q6-9 months
      3. Goal: 200 to 250 mg q3-4 weeks
    2. Maintenance
      1. Convert to Testosterone patches when at 200-250 mg
  8. Resources
    1. American Association for Klinefelter Syndrome
      1. http://www.aaksis.org
    2. Klinefelter Syndrome Support Group
      1. http://klinefeltersyndrome.org
  9. References
    1. Mendoki (1991) J Am Acad Child Adolesc Psychiatry 30
    2. Schwartz (1991) Endocrinol Metab Clin North Am 20:153
    3. Smyth (1998) Arch Intern Med 158(12):1309-14
    4. Behrman (2000) Nelson Pediatrics, Saunders, p. 1746-9
    5. Wattendorf (2005) Am Fam Physician 72:2259-62
    6. Wilson (1991) Harrison's Medicine, McGraw-Hill, p. 1800

Klinefelter Syndrome (C0022735)

Definition (NCI) A sex chromosome disorder caused by the presence of an extra X chromosome in the male karyotype. Affected individuals are infertile and have a small penis and testes. They tend to have tall stature and long legs and may have difficulties with speech and language development. Gynecomastia may be present.
Definition (MEDLINEPLUS)

Klinefelter's syndrome is a condition that occurs in men who have an extra X chromosome in most of their cells. The syndrome can affect different stages of physical, language and social development. The most common symptom is infertility. Because they often don't make as much of the male hormone testosterone as other boys, teenagers with Klinefelter's syndrome may have less facial and body hair and may be less muscular than other boys. They may have trouble using language to express themselves. They may be shy and have trouble fitting in.

It is important to start treatment as early as possible. With treatment, most boys grow up to have normal sex lives, successful careers and normal social relationships.Treatments include

  • Educational services
  • Physical, speech and occupational therapy
  • Medical treatments including testosterone replacement

NIH: National Institute of Child Health and Human Development
Definition (NCI) A genetic disorder in males caused by having one or more extra X chromosomes. Males with this disorder may have larger than normal breasts, a lack of facial and body hair, a rounded body type, and small testicles. They may learn to speak much later than other children and may have difficulty learning to read and write. Klinefelter syndrome increases the risk of developing extragonadal germ cell tumors and breast cancer.
Definition (JABL) A common sex chromosomal anomaly in males characterized mainly by small testes with tubular hyalinization, azospermia with infertility, slight breast enlargement, elevated urinary gonadotropins, and decreased urinary 17-ketosteroids. Dull mentality has been noted. The affected individuals appear normal after birth, except for small testes. Most characteristic features become evident at adolescence as hypogonadism, gynecomastia, incomplete virilization with variable eunuchoidism, and dull mentality. Without testosterone therapy, most adult patients may become obese. Occasional abnormalities may include cryptorchidism, hypospadias, ataxia, scoliosis during adolescence, and diabetes mellitus in adulthood.
Definition (CSP) genetic disease that produces sterile males with small testes lacking sperm due to XXY karyotype.
Definition (MSH) A form of male HYPOGONADISM, characterized by the presence of an extra X CHROMOSOME, small TESTES, seminiferous tubule dysgenesis, elevated levels of GONADOTROPINS, low serum TESTOSTERONE, underdeveloped secondary sex characteristics, and male infertility (INFERTILITY, MALE). Patients tend to have long legs and a slim, tall stature. GYNECOMASTIA is present in many of the patients. The classic form has the karyotype 47,XXY. Several karyotype variants include 48,XXYY; 48,XXXY; 49,XXXXY, and mosaic patterns ( 46,XY/47,XXY; 47,XXY/48,XXXY, etc.).
Concepts Congenital Abnormality (T019) , Disease or Syndrome (T047)
MSH D007713
ICD9 758.7
ICD10 Q98.0, Q98.4
SnomedCT 205712007, 205696000, 205701007, 405769009, 22053006, 157021007, 268357008, 405770005
English Syndrome, Klinefelter's, KLINEFELTER SYNDROME, KLINEFELTER'S SYNDROME, XXY SYNDROME, Klinefelter's karyotype 47,XXY, Klinefelter's syndrome NOS, Klinefelter's syndrome karyotype 47,XXY, Klinefelter's syndrome, unspecified, Klinefelter's Syndrome, XXY trisomy, seminiferous tubule dysgenesis, seminiferous tubule dysgenesis (diagnosis), XXY Klinefelter's syndrome (disorder), XXY Klinefelter's syndrome (diagnosis), XXY male, KLINEFELTER DISEASE, Klinefelter Syndrome, Klinefelter-Reifenstein-Albright syndrome, chromosome XXY syndrome, hypogonadotropic hypogonadism, primary hypogonadism, Klinefelter syndrome (KS), Klinefelter-Reifenstein syndrome, Xq Klinefelter syndrome, 47,XXY complex intersex, 47,XXY complex intersex (diagnosis), intersex complex 47,XXY, Klinefelter's syndrome NOS (disorder), Klinefelter syndrome, XXY, XXY Syndrome (Klinefelter Syndrome), Klinefelter syndrome karyotype 47, XXY, Klinefelter syndrome, unspecified, Klinefelter Syndrome [Disease/Finding], klinefelter's syndrome, XXY, Syndrome, XX Male, XX Male Syndromes, XX Male Syndrome, Syndromes, XX Male, chromosome xxy syndrome, xxy syndrome, klinefelter's syndrome, klinefelter 's syndrome, klinefelter disease, klinefelters syndrome, klinefelter's syndromes, Syndrome, XXY, XXY Syndromes, XXY Syndrome, Syndromes, XXY, Klinefelter Syndromes, Syndrome, Klinefelter, Syndromes, Klinefelter, XXY syndrome, Klinefelter's syndrome, Klinefelter syndrome, Klinefelter's syndrome karyotype 47 XXY, XXY Klinefelter's syndrome, Klinefelter's syndrome, XXY (disorder), Klinefelter's syndrome, XXY, Klinefelter, chromosome; anomaly, sex, Klinefelter, XXY; syndrome, hypogonadism; hypogonadotropic, hypogonadotropic; hypogonadism, karyotype; 47,XXY, Klinefelter, syndrome; XXY, anomaly; chromosomes, chromosomal, sex, Klinefelter, Klinefelter syndrome (disorder), Klinefelter's syndrome (disorder), Klinefelters Syndrome, Hypogonadotropic Hypogonadism, klinefelter syndrome
Portuguese SINDROME DE KLINEFELTER, Síndrome XXY, Síndrome de Klinefelter
Spanish SINDROME DE KLINEFELTER, Síndrome XXY, XXY Klinefelter's syndrome, Klinefelter's syndrome, síndrome de Klinefelter, SAI (trastorno), síndrome de Klinefelter, SAI, síndrome XXY, síndrome de Klinefelter (trastorno), síndrome de Klinefelter, síndrome de Klinefelter, XXY (trastorno), síndrome de Klinefelter, XXY, Sindrome de Klinefelter, Síndrome de Klinefelter
Dutch XXY syndroom, XXY; syndroom, anomalie; chromosomen, chromosomaal, geslacht, Klinefelter, chromosoom; anomalie, geslacht, Klinefelter, hypogonadisme; hypogonadotroop, hypogonadotroop; hypogonadisme, karyotype; 47,XXY, Klinefelter, syndroom; XXY, Syndroom van Klinefelter karyotype 47,XXY, Syndroom van Klinefelter, niet gespecificeerd, syndroom van Klinefelter, Klinefelter, syndroom van, Klinefeltersyndroom, Syndroom van Klinefelter
French Syndrome XXY, SYNDROME DE KLINEFELTER, Syndrome de Klinefelter
German XXY Syndrom, KLINEFELTER SYNDROM, Klinefelter-Syndrom, Karyotyp 47,XXY, Klinefelter-Syndrom, nicht naeher bezeichnet, Klinefelter Syndrom, Klinefelter-Syndrom
Italian Sindrome XXY, Sindrome di Klinefelter
Japanese ＸＸＹ症候群, XXYｼｮｳｺｳｸﾞﾝ, ｸﾗｲﾝﾌｪﾙﾀｰｼｮｳｺｳｸﾞﾝ, Klinefelter症候群, クラインフェルター症候群
Swedish Klinefelters syndrom
Czech Klinefelterův syndrom, XXY syndrom
Finnish Klinefelterin oireyhtymä
Russian KLAINFELTERA SINDROM, КЛАЙНФЕЛТЕРА СИНДРОМ
Korean 클라인펠터 증후군, 핵형 47, XXY, 상세불명의 클라인펠터 증후군
Polish Zespół Klinefeltera, Zespół XXY
Hungarian Klinefelter-syndroma, Xxy syndroma
Sources
Derived from the NIH UMLS (Unified Medical Language System)


Navigation Tree