Palatopharyngeal Incompetence
Clinical Features
Congenital palatopharyngeal incompetence is characterized by cleft palate speech (rhinolalia aperta) in the absence of overt cleft palate. About a fourth of cases are 'unmasked' by adenoidectomy. Abnormalities of the uvula, soft palate and hard palate may be visible. The inability to limit the flow of air-sound through the nose is responsible for the speech defect described as 'hypernasality' or 'nasal speech.' Occasionally dominant inheritance may obtain, with great variability, making this essentially a multifactorial trait. Andres et al. (1981) presented a family with the trait in multiple sibships of 3 generations with male-to-male transmission. The authors suspected a syndromal relationship to deafness in their family.
Vantrappen et al. (2002) described a kindred in which 10 members of 3 successive generations had isolated velopharyngeal insufficiency in an autosomal dominant pattern including 5 examples of male-to-male transmission. The index patient was referred for severe velopharyngeal insufficiency without overt or submucous cleft of the soft palate. A short and totally immobile soft palate was found with anatomic disproportion of the velopharyngeal structures. A younger brother had the same anomaly. He also presented with delayed speech development and hypernasal speech, due to the same radiologically confirmed short and immobile soft palate. Speech therapy was without avail; a pharyngoplasty brought moderate improvement. No abnormalities of mental and physical development and no cardiac abnormalities were found in members of this family. Karyotype was normal, and a deletion in 22q11 was excluded. None had manifestations of the velocardiofacial syndrome (192430).
Kannu et al. (2003) reported a family in which father-to-son transmission demonstrated autosomal dominant inheritance of velopharyngeal insufficiency. The 34-year-old father had nasal speech during childhood. He was unable to drink through straws or to speak loudly. Pharyngoplasty was performed at 8 years of age, with correction of speech. One of his 3 children had nasal speech at the age of 4.5 years and was found to have velopharyngeal insufficiency. Pharyngoplasty improved his speech quality. FISH analysis for the 22q11.2 deletion was negative, and a 550-resolution band karyotype was normal.
MappingZori et al. (1998) performed fluorescence in situ hybridization for locus D22S75 within the 22q11 region on 16 patients with velopharyngeal insufficiency of unknown cause and found that 6 had a deletion in the region.
In the families with velopharyngeal insufficiency described by Vantrappen et al. (2002) and Kannu et al. (2003), deletion in the 22q11 region was excluded.