We report six of 16 U.K. melanoma families and two of 17 patients with multiple primary melanomas and a negative family history who have between them four different functionally damaging mutations of the CDKN2A (p16) gene: an Arg 24 Pro substitution in exon 1 in one family, a stop codon at codon 44 of exon 1 in one family, and a Met 53 Ile substitution in exon 2 in four families. One multiple primary melanoma patient also has the Met 53 Ile mutation and a second has a G-T substitution at the IVS2 + 1 splice donor site. Our data together with other recent publications from France and the U.S.A. indicate that screening melanoma kindreds with only two affected family members for CDKN2A mutations is justified.

No abstract

Using S1 mapping and primer extension analysis, we have identified a number of human kappa-globin and beta-globin 5' RNA termini originating in the 200 bp upstream of the canonical mRNA cap sites. Upstream initiation sites have previously been reported for the human epsilon-globin gene (4,5) and the present work indicates that this is a general feature of the human beta-type globin genes. We have attempted to identify features common to such sites between the three genes. One site 170 bp upstream of the major beta-globin cap site and a site 1400 bp upstream of the major epsilon-globin cap site are located near putative PolIII promoter sequences and may therefore be transcribed by this enzyme. Alternative initiation sites located 200 bp and 50-100 bp upstream of the epsilon-globin and kappa-globin cap sites respectively are located within S1 hypersensitive regions of chromatin.

Complementary DNA (cDNA) was prepared with RNA-dependent DNA polymerase from human globin messenger RNA (mRNA). Annealing and translation experiments with total mRNA from circulating cells from a patient with heterozygous betaP/heterozygous beta-delta0 thalassemia (30/,6_0-thalassemia) The common genetic disease 13-thalassemia ((3-thal) is characterized by a reduced production of hemoglobin A (HbA, a2132), which results from the reduced synthesis of ,B-globin chains relative to a-globin chains, thus causing an imbalance in globin chain production and hence abnormal erythropoiesis (1). The (3-thalassemias show heterogeneity, and there are now several well-defined conditions that form this group.In some cases there is a partial deficiency of ,3-chain production (,3+-thal), in others a total deficiency of (3-chain production (,B0-thal), and finally there is a condition in which both the 6 chains of HbA2 (a262) and the 13-chains of HbA are not produced (6500-thal). It has been demonstrated previously that in many of these forms of (3-thalassemia there is a reduction in the amount of ,B-globin messenger RNA (mRNA). This is seen by the lack of mRNA translation activity in vivo and in homologous cell-free systems (2, 3), in heterologous cell-free systems (4-6), and by hybridization with complementary DNA (cDNA) prepared from globin mRNA with viral RNAdependent DNA polymerase (7-9). There is evidence, however, that in at least one variant of (-thalassemia, that originating in the Ferrara region of Italy, inactive globin Abbreviations: Dot, product of Do (initial concentration of cDNA in mol of nucleotide X liter-') and time (sec); Cot, product of CO (initial concentration of total DNA in mol of nucleotide X liter-') and time (sec). mRNA for ,B-globin chains is present (10,11). In all other types studied there appears to be a direct correspondence between the amount of (3-mRNA present and the amount of ,B-globin chain synthesized, both in homozygotes and heterozygotes.The (3, 6, and y-globin genes are thought to be adjacent to one another in a small region of a single chromosome (1,12 Recently it has been shown by cDNA/DNA hybridization techniques that in at least some cases the severe form of athalassemia is the result of a gene deletion involving all or a considerable part of the a-globin genes (13,14). In the present study we have applied similar techniques to see if the (3-globin genes are present in an individual heterozygous for both 30°-and 6300-thalassemia ((0/6(3O-thalassemia

Direct cDNA sequencing was performed on asymmetrically amplified transcripts from the porphobilinogen deaminase (PBG-D) gene of thirteen unrelated individuals with acute intermittent porphyria. Four different mutations and a polymorphic site were detected in exon 12 of the gene, four being the result of single base substitutions and one being caused by dinucleotide deletion. All of these mutations are located in domain 3 of the PBG-D molecule, with the single base substitutions affecting the hydrophobic interfaces between domains 1 and 3. The dinucleotide deletion results in a frame-shift producing a premature stop codon.