[Velofacial hypoplasia and submucous cleft palate: histologic analogies. A comparative histologic and histomorphometric study of velum musculature].

Velofacial hypoplasia (VFH) is particularly characterised by severe open nasalising with palate-throat insufficiency due to an abridged palatal velum. The cause of this disorder is unknown. Submucosal cleft palates (SMG), which may cause similar signs, are considered to be caused genetically, or acquired during pregnancy as an impedimental malformation. We compared histologically and histomorphometrically the palatal velums of patients with VFH and SMG, with normal specimens. In VFH and SMG, the muscle fibres of the palatal velums feature pathological variations of their diameters; moreover, these specimens contain more fibrous than muscle tissue compared with the controls. These changes do not indicate clearly either a neuropathogenic or a myopathogenic or other pathogenesis. However, the similarities of the clinical, histological and histomorphometric findings do indicate a common formal pathogenesis. Anamnestic examinations of the pregnancies (particularly of the first trimenon) of mothers of patients with VFH may reveal further findings supporting our assumption.