Down Syndrome Differential Diagnoses

Updated: Apr 21, 2022
  • Author: Gratias Tom Mundakel, MBBS, DCH; Chief Editor: Maria Descartes, MD  more...
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Diagnostic Considerations

The presence of eight or more of the characteristic clinical findings (see Presentation) leads to a definite diagnosis of Down syndrome. Chromosomal analysis is always recommended and of utmost importance in doubtful cases. [81, 82, 83]

In addition to the differential diagnosis, other problems to be considered include the following:

  • 49,XXXXY chromosome and other high-order multiple X chromosome disorders

  • Congenital hypothyroidism

  • Mosaic trisomy 21 syndrome

  • Partial trisomy 21 (or 21q duplication)

  • Robertsonian trisomy 21

  • Zellweger syndrome or other peroxisomal disorders

Differential Diagnoses