Talk:Monosomy
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Cite this page: Hill, M.A. (2024, April 26) Embryology Monosomy. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Monosomy |
2015
The Proportion of Diploid 46,XX Cells Increases with Time in Women with Turner Syndrome-A 10-year Follow-Up Study
Genet Test Mol Biomarkers. 2015 Jan 14. [Epub ahead of print]
Denes AM1, Landin-Wilhelmsen K, Wettergren Y, Bryman I, Hanson C.
Abstract
In the normal population, loss of one of the sex chromosomes leading to monosomy (45,X) is a part of the aging process. In Turner syndrome (TS), the classic karyotype 45,X is found in up to 50% at birth, and others have a second cell line; mosaicism. The aim was to study if the chromosomal pattern in TS women changes over time. Fluorescence in situ hybridization was performed on buccal smear cells obtained twice, 10 years apart, from 42 women with TS aged 26-66 years (mean±standard deviation: 42.0±11.6). DNA probes specific for chromosomes X (DXZ1) and Y (DYZ3) were used and >100 cells were analyzed/patient. Nineteen women had monosomy (45,X) (<10% 46,XX), nine had 45,X/46,XX mosaicism, and 14 had iso, ring, or a marker chromosome at baseline. At 10 years, the percentage of diploid cells had increased in 29 of 42 women (69%), with an average increase of 5.7±13.0%. There was a positive correlation between age and % change in diploid 46,XX or 46,XY cells (r=0.38, p=0.023). This new finding might have relevance for the life expectancy in TS.
PMID 25587646
2014
Turner syndrome-issues to consider for transition to adulthood
Br Med Bull. 2014 Dec 22. pii: ldu038. [Epub ahead of print]
Lucaccioni L1, Wong SC1, Smyth A2, Lyall H3, Dominiczak A4, Ahmed SF1, Mason A5.
Abstract
BACKGROUND: 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. AREAS OF AGREEMENT: 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. AREAS OF CONTROVERSY: Several unanswered questions remain, including the choice of hormone replacement therapy in the young person with TS and in adulthood; the optimal mode of cardiovascular assessment; the best management and assessment prior to and during pregnancy. AREAS TIMELY FOR DEVELOPING RESEARCH: The optimal model of care and transition to adult services in TS requires attention. Further research is needed in relation to cardiovascular risk assessment, pregnancy management and hormone replacement therapy in TS. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. KEYWORDS: Turner syndrome; aortic dilatation; aortic dissection; hormone replacement therapy; pregnancy; puberty; transition
PMID 25533182
2008
Monosomy 18p
Orphanet J Rare Dis. 2008 Feb 19;3:4. doi: 10.1186/1750-1172-3-4.
Turleau C1.
Abstract
Monosomy 18p refers to a chromosomal disorder resulting from the deletion of all or part of the short arm of chromosome 18. The incidence is estimated to be about 1:50,000 live-born infants. In the commonest form of the disorder, the dysmorphic syndrome is very moderate and non-specific. The main clinical features are short stature, round face with short philtrum, palpebral ptosis and large ears with detached pinnae. Intellectual deficiency is mild to moderate. A small subset of patients, about 10-15 percent of cases, present with severe brain/facial malformations evocative of holoprosencephaly spectrum disorders. In two-thirds of the cases, the 18p- syndrome is due to a mere terminal deletion occurring de novo, in one-third the following are possible: a de novo translocation with loss of 18p, malsegregation of a parental translocation or inversion, or a ring chr18. Parental transmission of the 18p- syndrome has been reported. Cytogenetic analysis is necessary to make a definite diagnosis. Recurrence risk for siblings is low in de novo deletions and translocations, but is significant if a parental rearrangement is present. Deletion 18p can be detected prenatally by amniocentesis or chorionic villus sampling and cytogenetic testing. Differential diagnosis may include a wide number of syndromes with short stature and mild intellectual deficiency. In young children, deletion 18p syndrome may be vaguely evocative of either Turner syndrome or trisomy 21. No specific treatment exists but speech therapy and early educational programs may help to improve the performances of the children. Except for the patients with severe brain malformations, the life expectancy does not seem significantly reduced.
PMID 18284672
2006
Cri du Chat syndrome
Orphanet J Rare Dis. 2006 Sep 5;1:33.
Cerruti Mainardi P1.
Abstract
The Cri du Chat syndrome (CdCS) is a genetic disease resulting from a deletion of variable size occurring on the short arm of chromosome 5 (5p-). The incidence ranges from 1:15,000 to 1:50,000 live-born infants. The main clinical features are a high-pitched monochromatic cry, microcephaly, broad nasal bridge, epicanthal folds, micrognathia, abnormal dermatoglyphics, and severe psychomotor and mental retardation. Malformations, although not very frequent, may be present: cardiac, neurological and renal abnormalities, preauricular tags, syndactyly, hypospadias, and cryptorchidism. Molecular cytogenetic analysis has allowed a cytogenetic and phenotypic map of 5p to be defined, even if results from the studies reported up to now are not completely in agreement. Genotype-phenotype correlation studies showed a clinical and cytogenetic variability. The identification of phenotypic subsets associated with a specific size and type of deletion is of diagnostic and prognostic relevance. Specific growth and psychomotor development charts have been established. Two genes, Semaphorin F (SEMAF) and delta-catenin (CTNND2), which have been mapped to the "critical regions", are potentially involved in cerebral development and their deletion may be associated with mental retardation in CdCS patients. Deletion of the telomerase reverse transcriptase (hTERT) gene, localised to 5p15.33, could contribute to the phenotypic changes in CdCS. The critical regions were recently refined by using array comparative genomic hybridisation. The cat-like cry critical region was further narrowed using quantitative polymerase chain reaction (PCR) and three candidate genes were characterised in this region. The diagnosis is based on typical clinical manifestations. Karyotype analysis and, in doubtful cases, FISH analysis will confirm the diagnosis. There is no specific therapy for CdCS but early rehabilitative and educational interventions improve the prognosis and considerable progress has been made in the social adjustment of CdCS patients. PMID 16953888
