Abstract for presentation at 11th International Congress of Human Genetics

Del 1q21.1 deletion/duplication syndrome. Further clinical delineation of this microdeletion syndrome most commonly presenting with congenital heart disease

  • John Bamforth, University of Alberta, Edmonton, Alberta, Canada
  • Dr Martin Somerville, University of Alberta, Edmonton, Alberta, Canada
  • Dr Ordan Lehmann, University of Alberta, Edmonton, Alberta, Canada
  • Dr John Dyck, University of Alberta, Edmonton, Alberta, Canada
  • Dr Edmond Lemire, Royal University Hospital, Saskatoon, Saskatchewan, Canada
  • Dr Steve Scherer, University of Toronto, Toronto, Ontario, Canada
  • Susan Christian, University of Alberta, Edmonton, Alberta
  • Mark Hicks, University of Alberta, Edmonton, Alberta, Canada

    • Three patients with chromosome 1q21.1 deletion syndrome were recently described by our group, the major clinical presentation being congenital heart disease. We report one more patient with a deletion and one other patient with a duplication of this region.
    Only one of the four cases was overtly dysmorphic and this patient had developmental delay. Although the other cases are much younger, they are developing normally.
    Birth weight and growth have been within the normal range, with the exception of the dysmorphic patient, who had well documented microcephally, resolving to -1 S.D. by the age of 10 years.
    The predominant cardiac lesion in all the deletion cases so far described involved the aortic arch. One case had a discrete coarctation of the aorta, two cases had post ductal interrupted aortic arch and one case had a preductal interrupted aortic arch. In two cases, reoperation was required for recurrent aortic stenosis.
    The patient with the duplication 1q21.1 presented with tetralogy of Fallot.
    One of the deletion patients who is old enough to cooperate with slit lamp examination has cataracts; examination of other cases is pending.
    In two of the three deletion cases that could be tested for parent of origin, the patients had inherited the deletion from a mother. The mothers were clinically healthy with no symptoms of heart disease. Two mothers have had normal EKG and echocardiographic examinations. The same two mothers have had slit lamp examination and have been shown to have asymptomatic lenticular opacities.
    The duplication case inherited her duplication from an asymptomatic father, who has a normal cardiac examination, but demonstrates asymptomatic lenticular opacities on slit lamp examination in a different distribution to the mothers who carry the deletions.
    The critical chromosomal region associated with the phenotype lies between D1S2344 and D1S2612, encompassing the connexin 50 gene, which may account for the cataract findings.
    This microdeletion syndrome appears to have pleomorphic clinical features and has usually been inherited from an affected parent. In both duplication and deletion cases, subtle eye findings are present in the affected parents who have been examined.

    Conference Organiser - ICMS Pty Ltd