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Educational Use Only - Embryology is an educational resource for learning concepts in embryological development, no clinical information is provided and content should not be used for any other purpose.


Monosomy refers to the presence of only one chromosome from the normal pair in the embryo. A partial monosomy is when there is only one copy of a segment of a chromosome present.

A complete monosomy syndrome in female humans is seen in Turner syndrome (Monosomy X) associated with either a missing or altered second X chromosome.

A partial monosomy syndrome in humans is seen in Cri du Chat (cat's cry) syndrome associated with a piece of chromosome 5 is missing.

Other described autosomal monosomies include chromosome 3, 7, 11, 18p and 21.

Genetic Links: Introduction | Genetic risk maternal age | Trisomy 21 | Trisomy 18 | Trisomy 13 | Trisomy X | Monosomy | Fragile X | Williams | Alagille | Philadelphia chromosome | Hydatidiform Mole | Epigenetics | Prenatal Diagnosis | Neonatal Diagnosis | International Classification of Diseases | Molecular Development - Genetics

| Genital System - Abnormalities

Some Recent Findings

  • Turner syndrome-issues to consider for transition to adulthood[1] "Turner syndrome (TS) is associated with a spectrum of health problems across the age span, which requires particular attention during the transition period in these adolescents. The majority of girls with TS require oestrogen replacement from puberty onwards, which is important for adequate feminization, uterine development and maintenance of bone health. There is a lifetime increased risk from autoimmune conditions like hypothyroidism, coeliac disease, hearing loss and aortic dilatation with the potential to lead to aortic dissection. A systematic and holistic approach to provision of health care in TS is needed."
More recent papers
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This table shows an automated computer PubMed search using the listed sub-heading term.

  • Therefore the list of references do not reflect any editorial selection of material based on content or relevance.
  • References appear in this list based upon the date of the actual page viewing.

References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.

Links: References | Discussion Page | Pubmed Most Recent | Journal Searches

Search term: Monosomy

Justin Rueckert, Katherine Devitt, Juli-Anne Gardner Renal Cell Carcinoma with monosomy 8: A Case Series and Review of the Literature. J Assoc Genet Technol: 2018, 44(1);5-9 PubMed 29550805

Honglei Zhang, Xing Yang, Xu Feng, Haibo Xu, Qin Yang, Li Zou, Mei Yan, Dequan Liu, Xiaosan Su, Baowei Jiao Chromosome-wide gene dosage rebalance may benefit tumor progression. Mol. Genet. Genomics: 2018; PubMed 29546464

Feng Suo, Chuangxia Wang, Tianya Liu, Yuan Fang, Qin Wu, Maosheng Gu, Lingshan Gou Non-invasive prenatal testing in detecting sex chromosome aneuploidy: A large-scale study in Xuzhou area of China. Clin. Chim. Acta: 2018; PubMed 29544746

D P Berry, A O'Brien, J O'Donovan, N McHugh, E Wall, S Randles, K McDermott, R E O'Connor, M A Patil, J Ho, A Kennedy, N Byrne, D C Purfield Aneuploidy in dizygotic twin sheep detected using genome-wide single nucleotide polymorphism data from two commonly used commercial vendors. Animal: 2018;1-8 PubMed 29540254

International Classification of Diseases

Chromosomal abnormalities, not elsewhere classified (Q90-Q99)

Q93 Monosomies and deletions from the autosomes, not elsewhere classified

Q96 Turner's syndrome Excl.: Noonan's syndrome (Q87.1)

Links: International Classification of Diseases

Prenatal Diagnosis

The most common prenatal diagnosis is by either amniocentesis or chorionic villi sampling.

Amniocentesis.jpg Cvs.jpg

Links:Amniocentesis | Chorionic villus sampling


Monosomic embryo icon.jpg
Page | Play

Monosomy X

Turner's syndrome karyotype

Monosomy XO or Turner's syndrome results in 99% non-viable embryos, viable development fail to sexually mature at puberty.

Named after Henry Turner (1938), an American clinician who first described the condition.

Turner Syndrome X Chromosome Variations.jpg Figure shows Turner syndrome variations of the second X chromosome.
  • Completely absent (45,X)
  • Partially absent
  • Forms an isochromosome (isoXq), possessing a long arm duplication (q) and being devoid of a short arm (p)
  • In a ring formation (rX)
  • Is devoid of the homeobox gene, SHOX (short stature homeobox), the deletion being prior to the junction between Xp22.2 and Xp22.3

Monosomy 18p Syndrome

Monosomy 18p syndrome facial features.jpg

Monosomy 18p syndrome facial features[2]

A flat midface, mild ptosis, large ears with detached pinnae and short protruding upper lip.

Jacobsen Syndrome

Jacobsen syndrome (JS) is a rare partial deletion of the long arm of chromosome 11.[3]

Cri du Chat Syndrome

Chromosome 5P deletions
Chromosome 5P deletions[4]

Chromosome 5P Deletion Syndrome or "Cri du Chat" (cat's cry) is a partial monosomy syndrome occurring in humans (1:15,000 to 1:50,000 live-born infants) associated with a piece of chromosome 5 is missing, see reviews.[4][5]

Cri du Chat - audio recording

Clinical Features Malformations (infrequently associated)
  • high-pitched monochromatic cry
  • severe psychomotor retardation.
  • severe mental retardation.
  • microcephaly
  • broad nasal bridge
  • epicanthal folds
  • micrognathia
  • abnormal dermatoglyphics
  • cardiac
  • other neurological
  • renal abnormalities
  • preauricular tags
  • syndactyly
  • hypospadias
  • cryptorchidism
Links: OMIM123450 | Cri du Chat - audio recording


  1. Laura Lucaccioni, Sze Choong Wong, Arlene Smyth, Helen Lyall, Anna Dominiczak, S Faisal Ahmed, Avril Mason Turner syndrome-issues to consider for transition to adulthood. Br. Med. Bull.: 2014; PubMed 25533182
  2. Catherine Turleau Monosomy 18p. Orphanet J Rare Dis: 2008, 3;4 PubMed 18284672 | PMC2265258 | Orphanet J Rare Dis.
  3. Teresa Mattina, Concetta Simona Perrotta, Paul Grossfeld Jacobsen syndrome. Orphanet J Rare Dis: 2009, 4;9 PubMed 19267933 | Orphanet J Rare Dis.
  4. 4.0 4.1 Paola Cerruti Mainardi Cri du Chat syndrome. Orphanet J Rare Dis: 2006, 1;33 PubMed 16953888
  5. Angela Rodríguez-Caballero, Daniel Torres-Lagares, Antonio Rodríguez-Pérez, María-Angeles Serrera-Figallo, José-María Hernández-Guisado, Guillermo Machuca-Portillo Cri du chat syndrome: a critical review. Med Oral Patol Oral Cir Bucal: 2010, 15(3);e473-8 PubMed 20038906


Pankaj Agarwal, Rajeev Philip, Manish Gutch, K K Gupta The other side of Turner's: Noonan's syndrome. Indian J Endocrinol Metab: 2013, 17(5);794-8 PubMed 24083159

David Hong, Jamie Scaletta Kent, Shelli Kesler Cognitive profile of Turner syndrome. Dev Disabil Res Rev: 2009, 15(4);270-8 PubMed 20014362

Catherine Turleau Monosomy 18p. Orphanet J Rare Dis: 2008, 3;4 PubMed 18284672

Paola Cerruti Mainardi Cri du Chat syndrome. Orphanet J Rare Dis: 2006, 1;33 PubMed 16953888

J Ross, A Zinn, E McCauley Neurodevelopmental and psychosocial aspects of Turner syndrome. Ment Retard Dev Disabil Res Rev: 2000, 6(2);135-41 PubMed 10899807


J L Ross, D Roeltgen, H Kushner, F Wei, A R Zinn The Turner syndrome-associated neurocognitive phenotype maps to distal Xp. Am. J. Hum. Genet.: 2000, 67(3);672-81 PubMed 10931762

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Cite this page: Hill, M.A. (2018, March 21) Embryology Monosomy. Retrieved from

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