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Certain birth defects, including neural tube defects and oral clefts, frequently co-occur. This association, termed schisis-association, is often lethal and linked to specific maternal and infant factors.
Area of Science:
- Medical Genetics
- Developmental Biology
- Pediatric Surgery
Background:
- Neural tube defects (anencephaly, encephalocele, spina bifida cystica), oral clefts, omphalocele, and diaphragmatic hernia are significant congenital anomalies.
- These defects are known to occur, but their non-random co-occurrence patterns require further investigation.
Purpose of the Study:
- To investigate the association rates of specific congenital abnormalities, particularly schisis-type defects.
- To identify demographic and clinical factors associated with these combined abnormalities.
Main Methods:
- Analysis of co-occurrence rates of neural tube defects, oral clefts, omphalocele, and diaphragmatic hernia.
- Statistical examination of sex ratio, twinning, presentation, birth weight, gestational age, maternal miscarriage rates, and sibling occurrence.
Main Results:
- Neural tube defects, oral clefts, omphalocele, and diaphragmatic hernia associate more frequently than expected by chance.
- The combined entity, termed schisis-association, is associated with higher rates in females, twins, breech presentations, lower birth weight, and shorter gestation.
- Maternal miscarriage rates were higher, and 3.7% of siblings were affected, primarily with isolated neural tube defects or oral clefts.
Conclusions:
- The observed co-occurrence of specific congenital abnormalities suggests underlying shared developmental pathways.
- Schisis-association represents a distinct, often lethal, clinical entity with identifiable risk factors.
- Further research into the etiology and management of these associated defects is warranted.
Abstract:
The neural tube defects (anencephaly, encephalocele, spina bifida cystica), oral clefts (cleft lip +/- palate, posterior cleft palate), omphalocele, and diaphragmatic hernia associate with one another far more frequently than at the expected random combination rates. The combination of other abnormalities does not exceed the expected rate. Thus, two or more combinations of schisis-type abnormalities without other defects were treated as a provisional entity. The schisis-association is practically a lethal abnormality. It occurs more often in girls (sex ratio: 0.33), in twins (4.6%), in breech presentations (13.7%), in association with lower mean birth weight (1,931 gm), and in association with a shorter gestation period (36.4 weeks). Mothers of affected children have a significantly higher miscarriage rate; occurrence of schisis-type abnormalities was found in 3.7% of the sibs of index patients. However, except for one, the sib-occurrences of schisis abnormalities were isolated neural tube defects or oral clefts.