Trsiomy 18 and Trisomy 13
Trisomy 13 (Patau syndrome) |
Trisomy 18 (Edwards syndrome) |
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1/ 14000 ( female = male) |
1/8000 ( female > male) |
incidence |
Severe MR |
neurological |
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Hypo or hypertonia Holoprosencephaly (single hemisphere with single ventricle) |
Hypertonia |
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Microcephaly |
head |
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Sloping forehead Scalp defects |
Prominent occiput |
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Micrognathia, dysplastic Low set ears |
face |
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Midline Cleft lip and palate |
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Eye anomalies (cataract, coloboma, micropthalmia (small eye) and corneal opacities) Closely-spaced eyes, single central eye (cyclopia) |
Small palpebral fissure
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polydactaly |
Clenched fist Rocker bottom clinodactyly, overlapping fingers (second and fifth overlap third and fourth) |
extremities |
Cardiac (88%),: VSD or PPA |
Cardiac (99%): vsd , pda |
Associated malformations |
renal |
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Pre & post-natal growth retardation |
growth |
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Some 50% of babies die in the first month and most of the rest in the first year. Survival beyond early infancy is rare and associated with profound learning disability. |
Only 5% lives > 1year and associated with profound learning disability. Most babies die in the first year of life. |
Life expectancy |
confirmed by chromosome analysis. Many affected fetuses are detected by ultrasound scan during the second trimester of pregnancy and diagnosis can be confirmed antenatally by amniocentesis and chromosome analysis. Can also be diagnosed on non-invasive prenatal testing (NIPT). |
diagnosis |
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Recurrence risk is low, except when the trisomy is due to a balanced chromosome rearrangement in one of the parents. |
Recurrence risk |