A cloned DNA segment from the telomeric region of human chromosome 4p is not detectably rearranged in Huntington disease patients.

Abstract

Genetic linkage studies have mapped the Huntington disease (HD) mutation to the distal region of the short arm of human chromosome 4. Analysis of recombination events in this region has produced contradictory locations for HD. One possible location is in the region distal to the D4S90 marker, which is located within 300 kilobases of the telomere. Other crossover events predict a more centromeric position for HD. Here we analyze the telomeric region of 4p in detail. Cloned DNA segments were derived from this region by utilizing a radiation-induced somatic cell hybrid as a source of DNA combined with preparative pulsed-field gel electrophoresis to enrich for the telomeric fraction. Additional DNA was obtained by using the cloned segments as multiple start points for cosmid walks. This strategy proved to be an effective method for cloning 250 kilobases of DNA in the region telomeric to D4S90. Hybridization analysis with the cloned DNA did not provide any evidence for the presence of rearrangements of 100 base pairs or greater in the DNA of individuals affected with HD. We also found no change in the size or structure of the 4p telomere in these samples.Huntington disease (HD) is a fatal neurodegenerative disorder of humans that is inherited as an autosomal dominant and highly penetrant trait (1). The disease usually begins between the ages of 30 and 45 years and progresses unremittingly for 15-20 years. Little is known about the biochemical basis of the disease. However, significant progress toward understanding HD has been achieved through genetic studies. In 1983, linkage analysis of two HD pedigrees mapped the mutation to the end of the short arm of chromosome 4, close to the polymorphic marker D4S10 (2). All subsequent families tested showed linkage to this region (3), suggesting that a single locus is mutated in all individuals affected by the disease. As HD also possesses a low mutation rate (1), the same mutation is generally believed to be present in all patients. This view is substantiated by genealogical studies that trace the disease to a single geographical origin (1) and by linkage disequilibrium studies that show that the disease probably arose from a single founder individual (4, 5). An additional feature of HD is that likely homozygotes show no more severe symptoms than heterozygotes, demonstrating that the disease is inherited in a completely dominant fashion (6).More recent meiotic linkage studies have mapped HD to the region between D4S10 and the 4p telomere (7) in a segment of DNA spanning -6000 kilobases (kb) (Fig. 1) FIG. 1. Possible locations for HD within the D4SJO-telomere region. The 6000-kb region extending from D4S10 to the 4p telomere is shown. The two likely positions for HD are indicated by the black bars; boundaries of the proximal location are presently defined by D4S10 on the centromeric side and marker A on the telomeric side, which represents the cluster of loci D4S96/D4S97/D4S115. identified, three suggest a telomeric location for the mutation (9, 11, 12). One of these c...

On planting alfalfa and growing orchids: the cloning of the gene causing Huntington disease

“…The cloning of the most telomeric segment of chromosome 4 was achieved using YAC technology (Bates et al 1990). This region was not detectably rearranged in Huntington disease patients (Pritchard et al 1990). Furthermore, the availability of the chromosome 4 specific cosmid libraries quickly allowed the development of cosmid contigs spanning hundreds of kilobases from both the proximal and distal candidate regions .…”

“…The next challenge was to identify closer and flanking markers for the HD gene which would then refine the minimal segment likely to contain this gene (Nakamuru et al 1988, Pohl et al 1988, Whaley et al 1988, Pritchard et al 1990, Weber et al 1992). Long-range mapping of these new markers by somatic cell hybrid panels, reduced radiation hybrids and pulsed field gel electrophoresis then defined physical distances to direct the molecular cloning.…”

Report of the committee on the genetic constitution of chromosome 4

“…Bates et al (1990Bates et al ( ,1991, Bucan et al (1990), ), dc Rooij et al (1991, Thompson et al (1991). Weber et al(l 991), Pritchard et al (1990), MacDonald etal(1991 4ql l-q l2 PDGFRA C platelet-derived growth factor receptor, alpha polypeptide A,R,S c Hsieh et al, 1991Buetow et al, 1991bStenman et al, 1989Matsui et al, 1989 4 q ll-q l3 AFP + alpha-fetoprotein A.R c Theuneet al, 1991 Orita et al, 1990 Locus Buetow et al, 1991bOrita et al, 1990Buetow and Murray, 1987 4qll-q21 D4S1 + DNA Segment, single copy probe 4c3.6 L.S C Buetow et al, 1991bDean et al, 1991b 4qll-q28 D4S138 + DNA Segment, single copy probe DM32 L,S P Morris et al, 1989a 4ql l-q31 D4S231 DNA Segment, single copy probes pYX9-10, YUNC A9-10FWD/YUNCA9-1OREV L,S P Buetow and Murray, 1991 4ql 1-qter D4S24 + DNA Segment, single copy probe G3D6 S P Gilliam et al, 1987 4ql 1-qter D4S27 + DNA Segment, single copy probe 4E8 S P Gilliam et al, 1987 4ql 1-qter D4S28 + DNA Segment, single copy probe C G I03 S P Gilliam et al, 1985 4ql 1-qter D4S29 + DNA Segment, single copy probe CG104 S P Gilliam et al, 1985 4ql 1-qter D4S30 + DNA Segment, single copy probe CG106 S P Gilliam et al, 1987 4ql 1-qter D4S31 + DNA Segment, single copy probe G1G12 S P Gilliam et al, 1987 4ql 1-qter D4S32 + DNA Segment, single copy (probe GDS1 aka C G 108) probe GDS 1 S P Gilliam et al, 1987 4ql 1-qter D4S33 + DNA Segment, single copy (probe GDS8 aka CG 128) probe GDS8 S P Gilliam et al, 1987 4ql 1-qter D4S36 + DNA Segment, single copy probe C G I02 S P Gilliam et al, 1985 4ql 1-qter D4S37 + DNA Segment, single copy probe CGI 10 S P Gilliam et al, 1985 4ql 1-qter D4S38 + DNA Segment, single copy probe 4F4 S P Gilliam et al, 1987 4ql 1-qter D4S45 + DNA Segment, single copy probe G1G9 S P Gilliam et al, 1987 4ql 1-qter PAICS phosphoribosylaminoimidazole carboxylase, phosphoribosylam...…”

Μοριακη Γενετικη Μελετη Της Χορειας Του Huntington Και Της Μυοτονικης Δυστροφιας Σε Ελληνικες Οικογενειες

“…Ενα χρόνο μετά την εργασία αυτή, δύο αμερικανικές ομάδες πραγματοποίησαν αντίστοιχες μελέτες με ηλεκτροφόρηση παλμού τμημάτων DNA της περιοχής 4ρ16.3 από χορειακούς ασθενείς, αλλά δεν αναγνώρισαν κάποια μεταβολή μεγέθους της τάξεως των μερικών εκατοντάδων ή χιλιάδων ζευγών βάσεων [154][155][156], Εικόνα ΙΙΙ.3. Εκτεταμένο γενεαλογικό δένδρο της οικογένειας Α, στην οποία εμφανίσθηκε μία σποραδική περίπτωση HD.…”