Excerpt from van der Woude Syndrome

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Background

van der Woude syndrome is an autosomal dominant syndrome characterized by a cleft lip or cleft palate, distinctive pits of the lower lips, or both. It is the most common syndrome associated with cleft lip or cleft palate. The degree to which individuals who carry the gene are affected widely varies, even within families. These variable manifestations include lower lip pits alone, absent teeth, or isolated cleft lip and cleft palate of varying severity. Hypodontia (absent teeth) has been increasingly recognized as a frequently associated anomaly. Many other associated anomalies have also been described.

Pathophysiology

The most prominent and consistent features of van der Woude syndrome are orofacial anomalies caused by an abnormal fusion of the palate and lips at 30-50 days postconception. Most cases of van der Woude syndrome have been linked to a deletion in chromosome 1q32-q41; however, a second chromosomal locus at 1p34 has also been identified. The responsible mutation has been identified in the interferon regulatory factor-6 (IRF-6) gene, but the exact mechanism of this mutation on craniofacial development is uncertain.

Demonstrating the presence or absence of an IRF-6 mutation can be helpful when distinguishing between uncomplicated cleft lip and/or cleft palate and van der Woude syndrome. A wide variety of chromosomal mutations that cause van der Woude syndrome and are associated with IRF-6 gene mutations have been described. A potential modifying gene has been identified at 17p11.2-p11.1. 

Frequency

International

In general, van der Woude syndrome affects about 1 in 100,000-200,000 individuals. About 1-2% of patients with cleft lip or cleft palate have van der Woude syndrome.

Mortality/Morbidity

The severity of van der Woude syndrome widely varies, even within families. Approximately 25% of individuals with van der Woude syndrome are asymptomatic or have minimal symptoms, such as absent teeth or trivial indentations in the lower lips. Others have severe clefting in the lip or palate. Lip pits are often associated with accessory salivary glands that empty into the pits, which occasionally leads to embarrassing visible discharge. Hypodontia is present in 10-81% of affected individuals. Most The upper and/or lower second premolars are frequently absent.

Race

Differences among races have not been described.

Sex

van der Woude syndrome equally affects both sexes.

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