Rieger syndrome with multiple chromosomal breaks and chromosome 4 deletion

Rieger syndrome (RS) is a rare autosomal dominant disorder with variable expressivity and complete penetrance. Axenfeld-Rieger syndrome (ARS) shows genetic heterogeneity with mutations in several chromosomal loci being implicated including PITX2, FOXC1 and PAX6. Cytogenetic analysis was done in this case. Patient had de novo 46,XY,del(4q25-q27) karyotype with a high percentage (>35%) of chromosomal breaks. The breaks were on different chromosomes and not related to disease phenotype of RS. Such chromosomal breaks are diagnostic of chromosomal instability syndromes. Available literature does not report chromosomal breaks in RS or due to culture condition. Such a high percentage of chromosomal breaks are associated with development of certain cancers. In the present case we did not find any features consistent with any of the chromosomal instability syndromes like Fanconi's anaemia and Blooms syndrome, but such cases need to be under regular follow-up. Thus RS cases with multiple chromosomal breaks need regular follow-up and genetic counselling.