The Waardenburg syndrome. Description and report of a search

Waardenburg syndrome: clinical differentiation between types I and II

Here we present the results of a study performed on 59 patients affected by Waardenburg syndrome (WS), 30 with the I variant, 21 having the type II, and 8 of them being isolated cases without telecanthus. These patients belong to 37 families; the main contributions and conclusions are based on the detailed study of 25 of these families, examined using standard procedures. All patients were examined as to the presence of eight cardinal signs important for the diagnosis of the condition; from each patient, from many of his/her normal relatives, and from a control sample of 300 normal individuals stratified by age and sex, 23 different craniofacial measurements were obtained. We also estimated, using our own data as well those collected from the literature, the frequencies of the cardinal signs, based on a total sample of 461 affected individuals with WSI and 121 with WSII. In order to originate discriminant functions to separate individuals affected by one of the two variants, both metric (from craniofacial measurements) as well as categoric data (based on the frequencies of the cardinal signs or symptoms) were used. Discriminant analysis based on the frequency of the eight cardinal signs can improve the separation of WSI patients without telecanthus from those presenting the variant II. We present also a Table with the conditional probabilities favoring the diagnosis of WSI for suspect subjects without telecanthus and any combination of the other seven signs/symptoms. The discriminant function based on the four ocular measurements (inner and outer intercanthal, interpupillary, and inferior lacrymal distances), on the other side, perfectly classifies patients affected by one of the variants of WS, the same taking place when the average values of the W index of all affected individuals per family are used. The discriminant function based solely in the individual W index values of patients correctly classifies 93% of WSII subjects, but only 60% of the patients with the I variant of WS.

Waardenburg syndrome type II: phenotypic findings and diagnostic criteria

The Waardenburg syndrome (WS) consists of at least two distinct autosomal dominant hereditary disorders. WS Type I has been mapped to the distal part of chromosome 2q and the gene identified as PAX3. Other gene(s) are responsible for WS Type II. Mapping WS Type II requires accurate diagnosis within affected families. To establish diagnostic criteria for WS Type II, 81 individuals from 21 families with Type II WS were personally studied, and compared with 60 personally studied patients from 8 families with Type I and 253 cases of WS (Type I or II) from the literature. Sensorineural hearing loss (77%) and heterochromia iridum (47%) were the two most important diagnostic indicators for WS Type II. Both were more common in Type II than in Type I. Other clinical manifestations, such as white forelock and skin patches, were more frequent in Type I. We estimate the frequency of phenotypic traits and propose diagnostic criteria for WS Type II. In practice, a diagnosis of WS Type II can be made with confidence given a family history of congenital hearing loss and pigmentary disorders, where individuals have been accurately measured for ocular distances to exclude dystopia canthorum.