Dissecting clinical findings: platelet defects segregate independently of deafness and cataract in a family affected by an apparent syndromic form of macrothrombocytopenia.
We studied a family with a suspected diagnosis of MYH9-related disease, which is one of the most common forms of autosomal dominant macrothrombocytopenias associated with hearing impairment, cataracts and nephritis. No mutation of the MYH9 gene was identified. Moreover, the A156V variant of the GPIbalpha gene, responsible for 30% of macrothrombocytopenias in Italy, was not detected in the family. Therefore, we hypothesized that the clinical symptoms were caused by mutations in different genes. The screening of the candidate genes for deafness and/or cataract allowed us to identify two variants, M34T and S19T, of the GJB2 gene in family members with hearing impairment. Because of the relatively common occurrence of inherited hearing loss and, at least in the Mediterranean area, of platelet macrocytosis, the two traits occurred by chance in the same family and mimicked the MYH9-related disease.
Gangarossa
Simone
S
ASL 7 Ragusa, Università di Bologna, Italy.
Seri
Marco
M
Pecci
Alessandro
A
Di Bari
Filomena
F
Cusano
Roberto
R
Balduini
Carlo
C
Gasparini
Paolo
P
Savoia
Anna
A
D002386:Cataract / Q000235:genetics*; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics; D004252:DNA Mutational Analysis; D003638:Deafness / Q000235:genetics*; D005192:Family Health; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D007558:Italy; D008297:Male; D020125:Mutation, Missense; D010375:Pedigree; D013577:Syndrome; D013921:Thrombocytopenia / Q000235:genetics* / Q000473:pathology
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26