Very short telomere length by flow fluorescence in situ hybridization identifies patients with dyskeratosis congenita.
Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome in which the known susceptibility genes (DKC1, TERC, and TERT) belong to the telomere maintenance pathway; patients with DC have very short telomeres. We used multicolor flow fluorescence in situ hybridization analysis of median telomere length in total blood leukocytes, granulocytes, lymphocytes, and several lymphocyte subsets to confirm the diagnosis of DC, distinguish patients with DC from unaffected family members, identify clinically silent DC carriers, and discriminate between patients with DC and those with other bone marrow failure disorders. We defined "very short" telomeres as below the first percentile measured among 400 healthy control subjects over the entire age range. Diagnostic sensitivity and specificity of very short telomeres for DC were more than 90% for total lymphocytes, CD45RA+/CD20- naive T cells, and CD20+ B cells. Granulocyte and total leukocyte assays were not specific; CD45RA- memory T cells and CD57+ NK/NKT were not sensitive. We observed very short telomeres in a clinically normal family member who subsequently developed DC. We propose adding leukocyte subset flow fluorescence in situ hybridization telomere length measurement to the evaluation of patients and families suspected to have DC, because the correct diagnosis will substantially affect patient management.
Alter
Blanche P
BP
Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD 20852-7231, USA. alterb@mail.nih.gov
Baerlocher
Gabriela M
GM
Savage
Sharon A
SA
Chanock
Stephen J
SJ
Weksler
Babette B
BB
Willner
Judith P
JP
Peters
June A
JA
Giri
Neelam
N
Lansdorp
Peter M
PM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD; D001855:Bone Marrow Diseases / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000628:therapy; D018797:Cell Cycle Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D019871:Dyskeratosis Congenita / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000628:therapy; D005434:Flow Cytometry; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007231:Infant, Newborn; D007962:Leukocytes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000235:genetics; D012313:RNA / Q000235:genetics; D019098:Telomerase / Q000235:genetics; D016615:Telomere / Q000235:genetics / Q000473:pathology
D015703:Antigens, CD; D018797:Cell Cycle Proteins; C112148:DKC1 protein, human; D009687:Nuclear Proteins; C422952:telomerase RNA; D012313:RNA; C509186:TERT protein, human; D019098:Telomerase