IJMed Genet 1994;31:933-936 933 Linkage of hereditary haemorrhagic telangiectasia to chromosome 9q34 and J Med Genet: first published as 10.1136/jmg.31.12.933 on 1 December 1994. Downloaded from evidence for locus heterogeneity Peter Heutink, Tjeerd Haitjema, Guido J Breedveld, Bart Janssen, Lodewijk A Sandkuijl, Carola J M Bontekoe, Cees J J Westerman, Ben A Oostra Abstract mostly appear as easily bleeding telangiectases Hereditary haemorrhagic telangiectasia in the skin and mucosa, but may also give (HHT) is an autosomal dominant disorder rise to larger arteriovenous malformations, for with unknown pathophysiology that is example, in the lung or in the brain. Clinical characterised by arteriovenous lesions and manifestations depend on the location and size recurrent haemorrhage in virtually every of the vascular anomaly: epistaxis is frequently organ. Linkage of HHT to markers on present, intestinal bleeding can occur, dys- chromosome 9q has recently been re- pnoea and cyanosis can arise from ar- ported. In this study we report con- teriovenous malformations in the pulmonary firmation of this localisation in three circulation, and bleeding of cerebral lesions unrelated families of Dutch origin. A may cause serious complications.'2 Since ther- fourth unrelated HHT family, in which apy can prevent a number of complications, considerably fewer pulmonary ar- case finding is useful. teriovenous malformations (PAVM) were The first patient with HHT was described present, yielded evidence for non-linkage by Babington3 in 1865; Rendu4 suggested a to this region. We conclude that HHT is hereditary trait as the cause for familial epistaxis a genetically heterogeneous disorder and and telangiectasia, which was confirmed by our results indicate that the presence of Osler5 and Weber.6 The prevalence of HHT PAVM may be more common in patients ranges between 1 to 2 per 100 000 and 1 per with a chromosome 9 linked form of HHT 10 000 with almost complete penetrance by the than in patients with the non-linked form. age of 40 years.79 The mode of inheritance is autosomal dominant. The disease occurs in all (J Med Genet 1994;31:933-936) races, and is equally frequent in both sexes.710 One homozygous child has been described who Hereditary haemorrhagic telangiectasia died of bleeding and hypoxaemia soon after (HHT), also known as Osler-Rendu-Weber dis- birth." Several earlier linkage studies led to http://jmg.bmj.com/ ease, is a rare disorder characterised by ar- inconclusive results owing to the low in- teriovenous communications which may formativeness of the markers used."1-'5 develop in virtually every organ.' These lesions In order to perform a systematic genome 2885 on September 30, 2021 by guest. Protected copyright. Department of Clinical Genetics, Erasmus University Rotterdam, PO Box 1738, 3000 DR Rotterdam, The Netherlands P Heutink G J Breedveld B Janssen L A Sandkuijl C J M Bontekoe 3186 3187 3185 B A Oostra Department of Pulmonology, St Antonius Hospital, 3 4 5 6 3 4 5 6 7 9 Nieuwegein, The Netherlands T Haitjema C J J Westerman 7 8 9 10 11 12 13 14 15 8 10 11 12 13 14 15 Correspondence to Dr Heutink. 16 17 Received 13 May 1994 15 16 17 Revised version accepted for publication 8 July 1994 Figure I Pedigrees offour HHTfamilies. Blood samples were obtained from numbered persons. 934 Heutink, Haitjema, Breedveld, Jranssen, Sandkuijl, Bontekoe, Westerman, Oostra search, as a first step in the "positional cloning" and family members participating in a family of the HHT gene, we collected blood samples screening study (manuscript in preparation). from four extended families (fig 1). Power All were investigated for the presence of mu- J Med Genet: first published as 10.1136/jmg.31.12.933 on 1 December 1994. Downloaded from calculations using SLINK'6 confirmed that the cocutaneous telangiectasia, including in- family material should provide sufficient in- spection of the nasal mucosa. All affected formation to detect linkage. persons were screened for pulmonary ar- The genome search was undertaken with a teriovenous malformations (PAVM) by chest selection of 350 highly polymorphic micro- radiography and measurement of arterial oxy- satellite markers evenly distributed over the genation. Intravenous digital subtraction human autosomes. During the course of our angiography (iv-DSA) of the pulmonary genome search, two reports of linkage of HHT circulation was performed in patients with ab- to markers on chromosome 9q were normalities on either chest radiography or in published.'718 This prompted us to test chro- arterial oxygenation. Also, iv-DSA of the ce- mosome 9q markers in our families. We report rebral circulation was done in all affected per- here linkage of HHT in three Dutch families to sons to screen for cerebral arteriovenous markers on chromosome 9q and recombination malformations (CAVM). events that allow us to define boundaries for the candidate region between two flanking markers DNA STUDIES on 9q34. The fourth family was not linked to Genomic DNA was isolated from peripheral the same chromosomal region. Heterogeneity blood as described by Miller et al.'9 Chro- analysis clearly indicated that HHT is a ge- mosome 9q microsatellites were selected based netically heterogeneous disorder. on available linkage maps.20-23 Microsatellite markers were amplified and analysed essentially as described by Weber and May.24 Briefly, mark- Subjects and methods ers were amplified in multiplex reactions in a FAMILY ASCERTAINMENT total volume of 11 g using 96 well plates (Co- The pedigrees of all four families are shown in star Thermowell 6509). Oligonucleotides for fig 1. Blood was obtained from HHT patients radioactive amplification were obtained with a c,en grant from the Netherlands Organization for 4' Distance (cM) Scientific Research (NWO). Additional oligo- D9S53 nucleotide primers were labelled during syn- thesis with Fluorescein Amidite (FluorePrime, Pharmacia, Sweden). Reactions were per- formed with 50 ng of genomic DNA, 40 ng fluorescein primer, 40 ng non-fluorescein primer, 10 mmol/l Tris pH 8 3, 1-5 mmol/l 4' MgCl2, 50 mmol/l KCI, 0-01% gelatin, D9S105 200,umol/l each dATP, dCTP, dGTP, dTTP, and 0 4 units Taq DNA Polymerase (Life Tech- http://jmg.bmj.com/ 7 nologies). PCR products were resolved according to D9S51 * D9S177 size by denaturing gel electrophoresis (5 5% Hydrolink, 40 W) using an ALF automated 6 sequencer (Pharmacia LKB Biotechnology D9S103G AB). Data were analysed with the Fragment software version 1-00 (Phar- Manager package on September 30, 2021 by guest. Protected copyright. 3 GSN macia LKB Biotechnology AB). LINKAGE ANALYSIS 8 Pairwise lod scores were calculated for each family using the MLINK program ofthe LINK- D9S60 AGE package, version 5- 125 assuming HHT to 2 IT HHT be an autosomal dominant disease with a gene D9S61 candidate frequency of 0-0001. At risk subjects were region grouped into three liability classes (30 years of 6 age or younger, 31 to 45 years, and older than D9S159 45 years) with penetrances of 0 5, 0 7, and 0 9 respectively. No allowance was made for AL 4 phenocopies. Mutation rate was set at zero and re- D9S179 combination rates in males and females were assumed to be equal. Marker allele frequencies were set equal. Calculation of pairwise lod D9S 164 scores with allele frequencies calculated from tel spouses did not substantially alter the results Figure 2 Schematic map of the HHT linked region on chromosome 9q34 with sex (<10%). average genetic distances based on previously published linkage maps.2 23 Each arrow In order to make multipoint analysis man- indicates one meiotic recombination event in an affected person in one of the linked the five most relevant markers were families. Dotted arrows indicate the possible location of a marker The double sided arrow ageable, indicates the minimum candidate region for HHT recoded to no more than five alleles each and Linkage of hereditary haemorrhagic telangiectasia to chromosome 9q34 935 Table I Two point lod scores between chromosome 9q markers and HHTfamilies 3186, and 3187 but not in family 3185. As- Marker Family Recombination fraction (0) suming genetic homogeneity we obtained a 0 00 0 01 0-05 0 10 0-20 maximum cumulative lod score (Zmax) of 3-95 J Med Genet: first published as 10.1136/jmg.31.12.933 on 1 December 1994. Downloaded from 0 30 between GSN and D9S6 1. Analysis of genetic D9S53 3185 -4 113 -0-675 -0-395 -0-143 -0-037 -0 003 3186 1-958 1-792 1-613 1-226 0-826 0-415 heterogeneity showed odds of 33:1 in favour 3187 0 612 0 559 0 504 0-388 0-266 0-138 of locus heterogeneity, with a peak lod score 2885 -4-576 0-822 -0-544 0-289 -0-158 -0-071 of5-47 between D9S6 1 and D9S 159 in support Totals -6-119 0-854 1-178 1-183 0-891 0-478 of D9S105 3181 0-139 0-196 0-215 0-179 0 095 0-023 both heterogeneity and linkage. The results 3186 1-971 1-819 1-654 1-288 0-872 0-406 of the HOMOG2 analysis showed that family 3187 NI NI NI NI NI NI not 2885 2-632 2-377 2-111 1-545 0-946 0-360 3185 is linked to the chromosome 9q locus Totals 4-742 4-392 3.979 3-012 1-913 0-798 (p< OOl0). D9S 177 3185 - 3-756 -1-721 -0-119 0-083 0-178 0-138 We performed recombination analysis in the 3186 2-107 2-104 1-930 1-746 1-358 0-941 3187 0-670 0-668 0 590 0-513 0 370 0-246 linked families by the construction of haplo- 2885 - 7-265 -3641 -0473 0-058 0-157 0-125 types for all markers along the chromosome, Totals - 8-244 2-590 1-928 2-284 2-063 1-450 because in the linkage analysis not all meiotic D9S51 3185 -0-065 -0050 -0-038 0-020 -0 009 -0-002 3186 2-782 2-552 2-313 1-806 1-257 0-660 events were informative.