title: Mosaic and partial monosomy of chromosome 21 in a case with low platelets count.
abstract: BACKGROUND
  Monosomy is defined as the presence of only one chromosome instead of two in humans. Partial monosomy occurs when only a portion of the chromosome is present in a single copy, while the rest has two copies. It can occur in unbalanced translocations or deletions.
  
  
  METHODS
  In this report, a 6 years old girl was presented who was referred to the Pediatric Dep, Shahid Sadoughi Hospital,Yazd, Iran, due to multiple congenital anomalies such as: frontal bossing, horizontal palpebral fissure, small deepest eyes, aplastic nasal bridge, broad philtrum, low set ears, large prominent ears, short neck, microcephaly, pectus excavatum, mental retardation, and dislocation of the hip. In peripheral blood smear, platelets were decreased but other hematological levels were normal. The karyotype result indicated a mosaic monosomy and partial monosomy of chromosome 21.
  
  
  CONCLUSIONS
  According to this and other case reports of monosomy of chromosome 21, this disease had very low prevalence rate among live infants or children. The present case had some congenital anomalies that present with abnormal medical condition. Therefore these patients must be evaluated for chromosomal studies.
authors.affiliation: Department of Pediatric Hematology oncology and Genetic Research Center, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Hashemi
authors.affiliation: Associate Professor in Genetics, PhD, Genetic Dept. Research & Clinical Centre for Infertility, Yazd, Iran.
authors.forename: Mh
authors.initials: M
authors.lastname: Sheikhha
authors.affiliation: Pediatric, Main University Hospital, Yazd Medical Sciences University, Yazd-Iran.
authors.forename: Ma
authors.initials: M
authors.lastname: Manouchehri
authors.affiliation: Associate Professor in Genetics, PhD, Genetic Dept. Research & Clinical Centre for Infertility, Yazd, Iran.
authors.forename: Sm
authors.initials: S
authors.lastname: Kalantar
keywords: Chromosome 21; Congenital anomalies; Partial monosomy; Platelets
references.citation: Cancer Genet Cytogenet. 2003 Apr 15;142(2):137-41
references.pmid: 12699891
references.citation: J Med Genet. 1998 Jul;35(7):604-8
references.pmid: 9678708
references.citation: Am J Hum Genet. 1995 Jul;57(1):62-71
references.pmid: 7611297
references.citation: Cancer Genet Cytogenet. 1992 Jul 15;61(2):122-5
references.pmid: 1638489
references.citation: J Intellect Disabil Res. 1998 Jun;42 ( Pt 3):254-8
references.pmid: 9678410
references.citation: Genomics. 1997 Jul 1;43(1):25-33
references.pmid: 9226369
references.citation: Eur J Med Genet. 2005 Apr-Jun;48(2):167-74
references.pmid: 16053908