chromosomal diseases

It is estimated that 50% of spontaneous abortuses during the early months of gestation have a demonstrable chromosomal abnormality; there are, in addition, numerous smaller detectable errors and many others still beyond our range of identification. About 1% of all newborn infants possess a gross chromosomal abnormality.

Types

 numerical chromosomal anomalies

• ploidy anomalies (aneuploidy)
  • triploidy
  • tetraploidy

• autosomal monosomies

• autosomal trisomies
  • trisomy 21 (Down syndrome)
  • trisomy 13
  • trisomy 18
  • trisomy 8
  • trisomy 9

• autosomal tetrasomies

 structural chromosomal anomalies

• deletions
  • chromsome 13 deletion
  • 18q- syndrome (del18q)
  • 18p- syndrome (del18p)
  • 4p- syndrome (del4p) (Wolf-Hischhorn syndrome)
  • 5p- syndrome (del5p) (cat-cry syndrome)
  • 11p- syndrome (del11p)
  • 17p- syndrome (Miller-Dieker syndrome)
  • isodicentric 22 (22pter-q11) (Schmid-Fraccaro syndrome)
  • 21q- syndrome (del21q)
  • 22q- syndrome (del22q)

 chromosomal duplications

 chromosomal recombinaisons

• recombinant chromsome 8 syndrome (RC8S)

 chromosomal translocations

 ring chromosomes

 gonosomal anomalies

• monosomy X (45,X) (Turner syndrome)
• 47,XXY
• 47,XXX
• 47,XYY

 mosaicism