Turner syndrome (mechanism of disease)

This is a flowchart on Turner syndrome, covering the etiology, pathophysiology, manifestations, and pharmacology/interventions.

ADDITIONAL TAGS:
Horseshoe kidneys
Risk factors / SDOH
Cell / tissue damage
Hormonal imbalance
Turner syndrome
Medicine / procedure
Infectious / microbial
Biochem / molecular bio
Other medical conditions
Signs / symptoms
Tests / imaging / labs
Embryology / development
Genetics / hereditary
Neurocog / psychiatry
Pathophysiology
+ Pharmacology
Etiology
Manifestations
Partially or completely missing an X chromosome
Sporadic nondisjunction of sex chromosomes during parental gamete meiosis → complete chromosomal monosomy
Karyotype:
45,XO / 46,XX
Sporadic nondisjunction of sex chromosomes during embryonic cell mitosis → sex chromosomal mosaicism
Karyotype: 45,XO (no Barr body)
Milder phenotype
Impaired ovarian development
Malfunctioning streak gonads with connective tissue replacing normal germ cells
↑ risk of X-linked recessive conditions
Low hairline (prominently in posterior)
Low-set ears
Small lower jaw; high arched palate
Wide, web-like neck; cystic hygroma
Shield-shaped chest
Aortic coarctation / dissection → rupture
Broad chest, wide-spaced nipples
Cubitus valgus
Renal malformations: horseshoe kidneys, renal agenesis
Short fingers and toes; nail dysplasia
Pregnancy
↓ estrogen;
↓ progesterone
Bicuspid aortic valve
One SHOX gene (on X chromosome) → short stature
↑ FSH, ↑ LH
Hashimoto thyroiditis
Type 2 diabetes mellitus
Osteoporosis → pathologic fractures
Delayed puberty
Primary amenorrhea
Infertility (except in IVF)
Estrogen and progesterone substitution
Surgical removal of streak gonads
Growth hormone therapy