Variable Expressivity of Wolfram Syndrome in a Family with Multiple Affected Subjects

Abstract

Purpose: To study the genetic basis and clinical manifestations of Wolfram syndrome in a multi-affected family.

Methods: Complete clinical examinations including urological, ophthalmic, neurological, and endocrinologic assessment were performed for three affected family members. Genomic DNA was extracted from peripheral blood leukocytes with salting out method and all WFS1 exons and their flanking regions were sequenced. Candidate variation was screened for segregation in the pedigree by Sanger sequencing.

Results: A known pathogenic missense mutation in WFS1 gene (c.1885C $>$ T which leads to p.Arg629Trp in the encoded protein) was identified in all affected individuals. Both clinical and genetic investigations confirmed Wolfram syndrome diagnosis with variable phenotypic features.

Conclusion: Identical mutations in the Wolfram syndrome causative gene can lead to variable manifestations of the syndrome even in the same family. Although the medical findings and clinical examination are imperative for the diagnosis of Wolfram syndrome, genetic testing is useful to confirm the diagnosis, especially in cases with possible reduced penetrance of the characteristic signs.

Keywords: WFS1 Gene; Wolfram Syndrome; Variable Clinical Manifestations.

Figure 1

Pedigree information of the Wolfram syndrome family. Black filled shapes represent affected patients. Open shapes represent unaffected members.

Figure 2

DNA sequence chromatograms of the identified WFS1 variation in three different genotypic features in the family.

Figure 3

Severe nerve fiber layer loss in cases V.2 and V.3.

Figure 4

Abdominopelvic sonography in case V.3 showing severe hydronephrosis in both kidneys.

Figure 5

(a) Tympanogram of both ears in case V.3. (b) Audiograms of case V.3 showing sensorineural hearing loss in both ears.

Figure 6

Severe optic atrophy with disc paleness in both eyes of case V.4.