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Mosaic trisomy 9

Disease definition

Mosaic trisomy 9 is a rare chromosomal anomaly syndrome, with a highly variable phenotype, principally characterized by intellectual disability, growth and developmental delay, facial dysmorphism (incl. microphthalmia, deep-set eyes, low-set, malformed ears, bulbous nose, high-arched palate, micrognathia) and congenital heart defects (e.g. ventricular septal defect), as well as urogenital (e.g. hypoplastic genitalia, cryptorchidism), skeletal (congenital joint dislocations or hyperflexion, scoliosis/kyphosis) and central nervous system anomalies (hydrocephalus, Dandy-Walker malformation). Pigmentary mosaic skin lesions along the lines of Blaschko are also frequently observed.


Classification level: Disorder
  • Synonym(s):
    • Mosaic trisomy chromosome 9
    • Trisomy 9 mosaicism
  • Prevalence: <1 / 1 000 000
  • Inheritance: -
  • Age of onset: Neonatal, Infancy
  • ICD-10: Q92.1
  • OMIM: -
  • UMLS: C2930908
  • MeSH: C535454
  • GARD: 43
  • MedDRA: -

Detailed information

General public

ERN produced/endorsed by ERN(s)   FSMR produced/endorsed by FSMR(s)
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