Family with 22-derived marker chromosome and late-onset dementia of the Alzheimer type: II. Further cytogenetic analysis of the marker and characterization of the high-level repeat sequences using fluorescence in situ hybridization.
Am J Med Genet
; 47(1): 14-9, 1993 Aug 01.
Article
em En
| MEDLINE
| ID: mdl-7690182
ABSTRACT
We have further characterized an unusual 22p+ marker chromosome with a double nucleolus organizer region (dNOR) previously identified in a family with late-onset dementia of the Alzheimer type. G-banding and morphology of the marker's q arm were typically normal. However, the p+ arm had a terminal cytological satellite and a GT-positive region at the midpoint. Standard C-banding documented 2 C-positive regions one was associated with the primary centromere; the other, which was at the midpoint of the p arm, was not associated with a constriction. With replication-banding, there was a darkly staining region in the middle of the p+ arm that resembled the pericentromeric region of a chromosome 21 or 22. Fluorescence in situ hybridization with pXlr 101, a probe recognizing the full repeating unit of rDNA, indicated that the marker had an unusually larger rDNA region; with pU 1.2, a probe recognizing the human rDNA promoter, the signal was a doublet. The marker had 2 signals with a beta-satellite probe, and a second signal in addition to that present at the primary centromere under low stringency with alpha-satellite probes and a classic satellite probe. Immunostaining of chromosome spreads after R-banding and ultraviolet (UV) denaturation showed that the major portion of the marker's p arm was highly methylated.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cromossomos Humanos Par 22
/
Marcadores Genéticos
/
Doença de Alzheimer
/
Região Organizadora do Nucléolo
Limite:
Aged
/
Female
/
Humans
Idioma:
En
Revista:
Am J Med Genet
Ano de publicação:
1993
Tipo de documento:
Article
País de afiliação:
Canadá