A de novo interstitial deletion of chromosome 15 band q25 as revealed by FISH-technique

• Published in: Clinical genetics Vol. 49; no. 6; p. 303
• Main Authors: Verma, R S, Kleyman, S M, Giridharan, R, Ramesh, K H
• Format: Journal Article
• Language: English
• Published: Denmark 01-06-1996
• Subjects: Chromosome Banding; Chromosome Deletion; Chromosomes, Human, Pair 15; Developmental Disabilities - genetics; Female; Humans; In Situ Hybridization, Fluorescence; Infant; Karyotyping
• ISSN: 0009-9163
• DOI: 10.1111/j.1399-0004.1996.tb03793.x

We report a new chromosomal finding in a 20 month-old girl. The minor clinical features included: moderate mental retardation, microcephaly, mild hypotonia and hypertelorism. Initially, what appeared to be a terminal deletion of the long arm of one chromosome 15 [15q26-->qter] was determined to be an interstitial deletion involving band 15q25 as revealed by FISH-technique, showing the presence of intact telomeric hybridization signals. The cytogenetic diagnosis was thus modified to 46,XX, del (15) (pter-->q24::q26--> qter). Nevertheless, the function of the enzyme telomerase should not be ignored, as healing could occur following such terminal deletions. Consequently, it will remain a difficult task to distinguish terminal deletions from those that are interstitial.