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No other birth defects were seen in 73.5%
of the children who had cleft lip with/without cleft palate
and 47.5% of those with cleft palate alone. |
 |
|
Chromosome abnormalities were seen in 7.9%
of those with cleft lip/palate and 9.8% with cleft palate
alone. The most common chromosome diagnoses were trisomy
13 (31%), trisomy 18 (18%) and Down syndrome (5%). |
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|
4% of children had a sequence—a collection
of birth defects all traceable to a single underlying
abnormality. About 8% of those with cleft palate had the
Robin sequence, where the tongue blocks palatal closure
causing a U-shaped cleft. Midline clefts were common in
the holoprosencephaly sequence. |
|
|
6% of oral clefts were attributed to genetic
disorders, in most cases, caused by autosomal dominant
genes. Common conditions include Stickler syndrome, craniosynostosis
syndromes and van der Woude syndrome (lip pits). 11% of
cleft palate cases had identified genetic conditions,
compared to only 2% of those with cleft lip with/without
cleft palate. |
|
|
There were only 9 cases attributed to known
environmental causes—mostly fetal alcohol syndrome
and fetal dilantin effects. |
|
|
About 19% had multiple birth defects of
unknown origin—about 15% of those with cleft lip/palate
and 22% of those with cleft palate alone. |
