A rare case of aniridia and balanced translocation (5;11) (p15.3;q22) arising in the same subject: a challenge for genetic counseling.
The authors report on a case of isolated aniridia caused by haploinsufficiency of the PAX6 gene, which is located on 11p13, and a balanced translocation t(5;l1)(p15.3;q22) inherited respectively from his father and his mother. Due to the coincidence of two abnormalities in the same chromosome, the segregation of the mutant allele leading to aniridia and of the chromosomes involved in the translocation are not independent events. Considering that both monosomy and trisomy for 11q22-qter are unviable, his offspring may inherit either the PAX6 mutation or the balanced translocation. However, depending on the occurrence of crossing over, there is a possibility for him to have normal offspring; on the other hand, he may also father children with both anomalies. This unusual case, in which the proband has a presumably very low chance of completely normal offspring, turned to be a challenge for genetic counseling.
Vulcani-Freitas
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TM
Department of Medical Genetics, Faculty of Medical Sciences, State University of Campinas (UNICAMP), São Paulo, Brazil.
Maciel-Guerra
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AT
D000328:Adult; D015783:Aniridia / Q000235:genetics*; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics*; D003434:Crossing Over, Genetic; D005136:Eye Proteins / Q000235:genetics; D005817:Genetic Counseling; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D008297:Male; D008540:Meiosis / Q000235:genetics; D009154:Mutation; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D014178:Translocation, Genetic
D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; C000605730:PAX6 protein, human; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins