Alström syndrome (OMIM 203800) is an autosomal recessive disease, characterized by cone-rod retinal dystrophy, cardiomyopathy and type 2 diabetes mellitus, that has been mapped to chromosome 2p13 (refs 1-5). We have studied an individual with Alström syndrome carrying a familial balanced reciprocal chromosome translocation (46, XY,t(2;11)(p13;q21)mat) involving the previously implicated critical region. We postulated that this individual was a compound heterozygote, carrying one copy of a gene disrupted by the translocation and the other copy disrupted by an intragenic mutation. We mapped the 2p13 breakpoint on the maternal allele to a genomic fragment of 1.7 kb which contains exon 4 and the start of exon 5 of a newly discovered gene (ALMS1); we detected a frameshift mutation in the paternal copy of the gene. The 12.9-kb transcript of ALMS1 encodes a protein of 4,169 amino acids whose function is unknown. The protein contains a large tandem-repeat domain comprising 34 imperfect repetitions of 47 amino acids. We have detected six different mutations (two nonsense and four frameshift mutations causing premature stop codons) in seven families, confirming that ALMS1 is the gene underlying Alström syndrome. We believe that ALMS1 is the first human disease gene characterized by autosomal recessive inheritance to be identified as a result of a balanced reciprocal translocation.Alström syndrome was initially mapped to an interval of 6.1 cM between loci D2S286 and D2S327 (refs 3-5). Although several candidate genes have been investigated, no mutations have previously been identified [6][7][8] . We have shown that the 2p13 breakpoint in the individual with the 46,XY,t(2;11)(p13;q21)mat translocation is between these loci by metaphase fluorescence in situ hybridization (FISH) analysis using the BACs RP11-355F16 (containing D2S286) and RP11-480F1 (located 150 kb proximal to D2S327) as probes. The BAC RP11-582H21 crosses the translocation breakpoint (Fig. 1a,b) and is overlapped by RP11-79N18, which contains CCT7, a member of a chaperonin gene

The Jervell and Lange-Nielsen syndrome (JLNS) comprises profound congenital sensorineural deafness associated with syncopal episodes. These are caused by ventricular arrhythmias secondary to abnormal repolarisation, manifested by a prolonged QT interval on the electrocardiogram. Recently, in families with JLNS, Neyroud et al. reported homozygosity for a single mutation in KVLQT1 , a gene which has previously been shown to be mutated in families with dominantly inherited isolated long QT syndrome [Neyroud et al . (1997) Nature Genet ., 15, 186-189]. We have analysed a group of families with JLNS and shown that the majority are consistent with mutation at this locus: five families of differing ethnic backgrounds were homozygous by descent for markers close to the KVLQT1 gene and a further three families from the same geographical region were shown to be homozygous for a common haplotype and to have the same homozygous mutation of the KVLQT1 gene. However, analysis of a single small consanguineous family excluded linkage to the KVLQT1 gene, establishing genetic heterogeneity in JLNS. The affected children in this family were homozygous by descent for markers on chromosome 21, in a region containing the gene IsK . This codes for a transmembrane protein known to associate with KVLQT1 to form the slow component of the delayed rectifier potassium channel. Sequencing of the affected boys showed a homozygous mutation, demonstrating that mutation in the IsK gene may be a rare cause of JLNS and that an indistinguishable phenotype can arise from mutations in either of the two interacting molecules.

In patients who are in functionally poorer condition after the Fontan operation, portal venous flow loses normal expiratory augmentation and adverse gravity influence is enhanced. These suboptimal flow dynamics, coupled with higher splanchnic venous pressures and lower transhepatic venous pressure gradients, suggest that hepatic sinusoids are congested, acting as "open tubes." Transhepatic gradient loss is incrementally worse with higher caval pressures. These observations may be responsible for late gastrointestinal problems in patients who have had the Fontan operation.

and premature closure of foramen ovale. Myocardial sinusoids and coronary arteriovenous fistula serving as outflow channel. Am Heart J 70: 476, 1965 24. Steeg CN, Ellis K, Bransilver B, Gersony W: Pulmonary atresia and intact ventricular septum complicating corrected transposition of the great vessels. Am Heart J 82: 382, 1971 entirely overgrown by hypertrophied myocardium. With this appreciation of the variety of ventricular morphology encountered, we have reviewed the results of our surgical management of PA:IVS over the past 10 years. This retrospective study forms the basis of a prospective management protocol both for the neonatal period, when mortality is high, and for definitive repair later. The question of right ventricular growth and the comparability of critical pulmonary stenosis to PA:LVS are also discussed. MethodsThe records of 81 patients admitted to the Hospital for Sick Children from 1970 to 1980 inclusive were examined. Sixty patients had PA:LVS and 21 had critical pulmonary stenosis. Patients with critical pulmonary stenosis were included only if they required operation in the first month of life, with suprasystemic pressures in the right ventricle, right-to-left shunting at atrial level and a pinhole patency of the pulmonary valve at angiography. Patients with PA:IVS were included regardless of age at initial operation. Even in the presence of extreme right ventricular hypoplasia, both lesions were considered amenable to surgical treatment throughout the period reviewed.Details of the use of prostaglandin infusion, the na-2712 CIRCULATION

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