Most cases of Edwards syndrome occur due to problems during the formation of the reproductive cells or during early development. The rate of disease increases with the mother's age. Rarely cases may be inherited from a person's parents. Occasionally not all cells have the extra chromosome, known asmosaic trisomy, and symptoms in these cases may be less severe.[2] Ultrasoundcan increase suspicion for the condition, which can be confirmed byamniocentesis.[1]
Treatment is supportive. After having one child with the condition, the risk of having a second is typically around one percent.[1] It is the second-most frequent condition due to a third chromosome at birth, after Down syndrome.[3]
Edwards syndrome occurs in around one in 5,000 live births.[2] Some studies suggest that more babies that survive to birth are female.[1] Many of those affected die before birth. Survival beyond a year of life is around 5-25%.[2] It is named after John Hilton Edwards, who first described the syndrome in 1960.
Signs and symptoms
Clenched hand and overlapping fingers: index finger overlaps third finger and fifth finger overlaps fourth finger, characteristically seen in trisomy 18
Children born with Edwards syndrome may have some or all of these characteristics: kidney malformations, structural heart defects at birth (i.e.,ventricular septal defect, atrial septal defect, patent ductus arteriosus), intestines protruding outside the body (omphalocele), esophageal atresia,intellectual disability, developmental delays, growth deficiency, feeding difficulties, breathing difficulties, and arthrogryposis (a muscle disorder that causes multiple joint contractures at birth).[5][6]
Some physical malformations associated with Edwards syndrome include small head (microcephaly) accompanied by a prominent back portion of the head (occiput), low-set, malformed ears, abnormally small jaw (micrognathia), cleft lip/cleft palate, upturned nose, narrow eyelid folds (palpebral fissures), widely spaced eyes (ocular hypertelorism), drooping of the upper eyelids (ptosis), a short breast bone, clenched hands, choroid plexus cysts, underdeveloped thumbs and/or nails, absent radius, webbing of the second and third toes,clubfoot or rocker bottom feet, and in males, undescended testicles.[5][6]
In utero, the most common characteristic is cardiac anomalies, followed by central nervous system anomalies such as head shape abnormalities. The most common intracranial anomaly is the presence of choroid plexus cysts, which are pockets of fluid on the brain. These are not problematic in themselves, but their presence may be a marker for trisomy 18.[7][8] Sometimes, excess amniotic fluidor polyhydramnios is exhibited.[5]
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