Trisomy Definition
This disorder is a form of aneuploidy that has a presence of 3 copies instead of the normal 2, of a particular chromosome. An extra chromosome 21, found in Down syndrome, is called trisomy 21.
Trisomy Diagnosis
To diagnose the disease, conventional cytogenetic studies may be conducted. Echocardiography is performed for cardiac anomalies while barium swallow is an option for gastrointestinal anomalies. Genitourinary anomalies may be discovered through an ultrasonography.
Trisomy Treatment
There is no cure for the disease and medical care is supportive. Treatment of infections should be continuous. For feedings problems, nasogastric and gastrostomy supplementation should be done. Surgical repair of severe congenital anomalies such as esophageal atresia or congenital heart defects is not seen to improve the survival rate of infants.
Trisomy Symptoms and Signs
Symptoms of the disease include neonatal hypotonia followed by hypertonia, jitteriness, apnea, and seizures. Cranial abnormalities such as microcephaly, elongated skull, narrow bifrontal diameter, wide fontanels, and prominent occiput may be observed in patients. Facial abnormalities may also be present, which includes narrow palatal arch, infrequent cleft lip and cleft palate, preauricular tags and low-set, malformed ears.
Trisomy Causes
In full trisomy, the non-disjunction of the cells when dividing to form an egg and sperm cell causes the abnormality. Partial trisomy meanwhile occurs when part of an extra chromosome is attached to one of the other chromosomes. A mosaic trisomy meanwhile happens when extra chromosomal material exists in only some of the organism's cells.
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