The first Icelandic family with X-linked agammaglobulinaemia: studies of genetic markers and immune function.

This paper describes studies of genetic markers and immune functions in the first Icelandic family identified with X-linked agammaglobulinaemia (X-LA), including three affected brothers. The eldest brother was diagnosed at the age of 9 in 1963. He suffered repeated infections and died at the age of 23. The other two affected brothers, diagnosed at 6 years and 1 year of age, are alive and well on immunoglobulin replacement therapy at the ages of 32 and 24. All were typed for HLA, complement, and various other markers. Pedigree analysis suggests an X-linked segregation of the disease. Their serum IgG is maintained at normal levels on therapy. Several parameters of immune function were studied. The following results were obtained for the X-LA brothers: B cells are absent in their peripheral blood samples. T-cell numbers are normal, but monocytes are increased in numbers and activity. No immunoglobulin production could be elicited in vitro with PWM and no cells containing cytoplasmic Ig were detectable among PWM-stimulated blasts. Nevertheless the proliferative response was particularly vigorous, but the responding cells were shown to be exclusively T cells. No blast transformation could be achieved with EB virus. NK-cell activity was normal/high normal. Other cell-mediated immune functions were normal. In conclusion our data indicate that the differentiation of B cells is blocked in the two surviving X-LA brothers. They have survived for a longer time and in better health than is generally reported. Early diagnosis and adequate replacement treatment with Ig is clearly crucial. Vigorous non-specific immune mechanisms may help to compensate for the defective specific immunity.

Genetic linkage map of 46 DNA markers on human chromosome 16.

We have constructed a genetic linkage map of human chromosome 16 based on 46 DNA markers that detect restriction fragment length polymorphisms. Segregation data were collected on a set of multigenerational families provided by the Centre d'Etude du Polymorphisme Humain, and maps were constructed using recently developed multipoint analysis techniques. The map spans 115 centimorgans (cM) in males and 193 cM in females. Over much of the chromosome there is a significantly higher frequency of recombination in females than males. Near the alpha-globin locus on the distal part of the short arm, however, there is a significant excess of male recombination. Twenty-seven (59%) of the markers on the map have heterozygosities greater than or equal to 0.50. The largest interval between loci on the sex-average map is 14 cM and the average marker spacing is 3 cM. Using loci on this map, one could detect linkage to a dominant disease on chromosome 16 with as few as 10-15 phase-known meioses.

Molecular nature of in vivo mutations in human cells at the autosomal HLA-A locus.

The mutations present in vivo in normal human cells were studied at the HLA-A locus by isolating mutant lymphocytes using antibody-complement immunoselection and cloning at limiting dilution. The molecular basis for mutation in 127 mutant lymphocytes from 10 individuals was determined by studying a variety of polymorphic gene loci on both arms of chromosome 6. No change was detected in 78 mutants (61.4%), gene deletion was detected in 11 (8.7%), and mitotic recombination was detected in 38 (29.9%). Neither gene conversion nor chromosome loss was detected. These observations document the mechanisms responsible for gene loss in normal human cells in vivo, emphasize the importance of mitotic recombination, and indicate the similarity between mutational mechanisms in normal cells and in cancer cells.

Evidence against close linkage of unipolar affective illness to human chromosome 11p markers HRAS1 and INS and chromosome Xq marker DXS52.

The genetic basis of various subtypes of the affective disorders has been investigated by family, twin, and adoption studies, as well as by segregation and linkage analysis. Linkage analyses of bipolar disorder with the chromosome 11p15 DNA markers HRAS1 and INS, and the chromosome Xq28 markers for color blindness and G6PD have been reported. We have used restriction fragment length polymorphisms as markers to examine linkage in three extended families with unipolar affective illness, ascertained through probands with either recurrent unipolar or bipolar II illness. Using an inclusive definition of the affected phenotype, linkage could be excluded up to 28cM around the HRAS1-INS linkage group on chromosome 11p15, and up to 5 cM around the DNA marker DXS52 on Xq28. Negative linkage results were also obtained for two more restrictive definitions of affective illness. Thus, we find no evidence for the involvement of the chromosomal regions 11p15 and Xq28 with unipolar affective disorder in these three families.

Chromosome 17p deletions and p53 gene mutations associated with the formation of malignant neurofibrosarcomas in von Recklinghausen neurofibromatosis.

von Recklinghausen neurofibromatosis (NF1) is a common hereditary disorder characterized by neural crest-derived tumors, particularly benign neurofibromas whose malignant transformation to neurofibrosarcomas can be fatal. The NF1 gene has been mapped to a small region of chromosome 17q, but neither the nature of the primary defect nor the mechanisms involved in tumor progression are understood. We have tested whether NF1 might be caused by the inactivation of a tumor suppressor gene on 17q, analogous to that on chromosome 22 in NF2, by searching for deletions of chromosome 17 in NF1-derived tumor specimens. Both neurofibrosarcomas from patients with "atypical" NF and 5 of 6 neurofibrosarcomas from NF1 patients displayed loss of alleles for polymorphic DNA markers on chromosome 17. However, the common region of deletion was on 17p and did not include the NF1 region of 17q. Since no loss of markers on chromosome 17 was observed in any of 30 benign tumors from NF1 patients, the 17p deletions seen in neurofibrosarcomas are probably associated with tumor progression and/or malignancy. This region contains a candidate gene for tumor progression, p53, which has recently been implicated in the progression of a broad array of human cancers. In a preliminary search for p53 aberrations by direct sequencing of polymerase chain reaction-amplified DNA from 7 neurofibrosarcomas, 2 tumors that contained point mutations in exon 4 of the p53 gene were found, suggesting a role for this gene in at least some neurofibrosarcomas. Thus the formation of malignant neurofibrosarcomas may result from several independent genetic events including mutation of the NF1 gene, whose mechanism of tumorigenesis remains uncertain, and subsequent loss of a "tumor suppressor" gene on 17p, most likely p53.

[Malignancies in families of children with cancer]. / Malignome in Familien mit krebskranken Kindern.

We examined the frequency and kind of cancer in families with a child having a neoplasm at the Universitätskinderklinik Homburg/Saar, at the Universitätskinderklinik Freiburg and at the Institut für Medizinische Statistik und Dokumentation der Johannes Gutenberg-Universität Mainz. The following could be shown: 1. There is no difference in the distribution of various kinds of cancer in children, whether they have relatives with cancer or not. 2. It is necessary to examine the family history repeatedly to obtain an accurate documentation of familial cancer. 3. Cancer in familial members did occur in a third of all families on an average. 4. Independently of the diagnosis of the child, in most families only one additional family member did have cancer. 5. The majority of relatives with cancer are grandparents. 6. Cancer of the lung and of the breast are the most frequent kinds of neoplasms occurring in family members. 7. Comparing the most frequent kinds of neoplasms in family members in this study with the distribution of cancer in adults, it is obviously, that there is a higher percentage of leukemia and brain tumors in relatives of children with cancer than is expected. 8. Typical tumor constellations can be found in affected families like breast cancer and soft tissue sarcomas.

No evidence for genetic linkage of Gilles de la Tourette syndrome on chromosomes 7 and 18.

Gilles de la Tourette syndrome is a heritable neuropsychiatric disorder. In order to determine the chromosomal localisation of the locus involved, genetic linkage studies were initiated in six extended families. The Gilles de la Tourette gene has been tentatively assigned to chromosome 18q22.1. In our present study no evidence for genetic linkage on chromosome 18 and chromosome 7 was obtained. Data from the markers tested made it possible to exclude the whole of chromosome 18 and the chromosome 7q21.3-qter region as a site for the Gilles de la Tourette gene.

Translated translational operator in Escherichia coli. Auto-regulation in the infC-rpmI-rplT operon.

The genes coding for translation initiation factor IF3 (infC) and for the ribosomal proteins L35 (rpmI) and L20 (rplT) are transcribed in that order from a promoter in front of infC. The last two cistrons of the operon (rpmI and rplT) can be transcribed from a weak secondary promoter situated within the first cistron (infC). Previous experiments have shown that the expression of infC, the first cistron of the operon, is negatively autoregulated at the translational level and that the abnormal AUU initiation codon of infC is responsible for the control. We show that the expression of the last cistron (rplT) is also autoregulated at the posttranscriptional level. The L20 concentration regulates the level of rplT expression by acting in trans at a site located within the first cistron (infC) and thus different from that at which IF3 is known to act. This regulatory site, several hundred nucleotides upstream from the target gene (rplT), was identified through deletions, insertions and a point mutation. Thus, the expression of the operon is controlled in trans by the products of two different cistrons acting at two different sites. The localization within an open reading frame (infC) of a regulatory site acting in cis on the translation of a downstream gene (rplT) is new and was unforeseen since ribosomes translating through the regulatory site might be expected to impair either the binding of L20 or the mRNA secondary structure change caused by the binding. The possible competition between translation of the regions acting in cis and the regulation of the expression of the target gene is discussed.

Quantitative relationship between mutagenic potency in the Ara test of Salmonella typhimurium and carcinogenic potency in rodents. A study of 11 direct-acting monofunctional alkylating agents.

This work attempted to derive a quantitative relationship between mutagenicity and carcinogenicity by examining the association between mutagenic potency in the Ara test of Salmonella typhimurium and carcinogenic potency in rodents. Mutagenesis was monitored by selecting forward mutations to L-arabinose resistance. Lethality was measured at equivalent experimental conditions to those of mutant yield by using a mixed population of a pair of isogenic strains distinguished by their differential nutritional requirements. The study was carried out with a group of 11 direct-acting monofunctional alkylating agents, which failed to show any quantitative correlation in the histidine reverse-mutation test. Our data suggest that the mutagenic efficiency of the compounds is directly proportional to the magnitude of the maximum yield of L-arabinose resistance mutants and inversely proportional to the dose and the number of lethal hits at which the maximum yield occurs. A highly significant correlation (r10 = 0.86, P less than 0.01) was found between the mutagenic efficiencies of the compounds in the Ara test and their carcinogenic potencies in rodents, expressed as TD50 ('tumor dose' 50) values. The result suggests that the Ara forward-mutation test of S. typhimurium might be capable of reflecting the relative potency of animal carcinogens, at least when confined to particular chemical classes. A more generic and definitive conclusion about the predictive value of the Ara test would require this analysis to be extended to other types of genotoxic carcinogens.

[Migration of the Walser population]. / Die Migration der Walser.

Migrations in prehistoric and protohistoric man are responsible for the genetic similarity observable in recent populations. As a consequence of these early migrations, small groups were founded and the resultant genetic drift and isolation were often involved in the differentiation of some populations. The Walsers of the Grisons (Switzerland) present a good example of these inter-related population-genetic phenomena: migration was the major determinant of the relatedness of the gene pool in all Walser populations. This can be proven by allele frequencies, and most convincingly by electrophoretic variants which are only shared by closely related Walser groups. This statement demonstrates clearly the congruence of the genetics and well-documented population history of the Walsers. Incidentally, blood genetic and demographic data support the hypothesis that a genetical cline exists in the valley of Safien from south to north. This is in accordance with the historical data describing the peopling of the valley by Rheinwald Walsers in the 14th to the 16th century.

Qualitative dermatoglyphic affinities between the migrant groups of fishermen of Puri Coast, India.

Finger and palm prints of 677 subjects (395 males and 282 females) were analyzed for 11 qualitative dermatoglyphic variables to study the relationship between the three migrant groups of fishermen of Puri. Sanghvi's X2-distance gives configuration confirmatory to caste affiliations, quite clearly in males, but to a lesser degree in females. A comparison with distance configurations obtained for quantitative finger/palm variables and for anthropometric/genetic markers suggests that the qualitative dermatoglyphic traits stand out as useful markers in more convincingly portraying the affinities at the level of sub-castes.

Somatovariants of Sardinian recruits from the three principal geographic areas of the island.

Using the constitutional method based on somatovariants, three samples with a total of 1207 recruits, divided according to the three main geographic areas of Sardinia (North, Center, South) were compared. Individuals from the center of the island are lighter and shorter than those belonging to the other two regions. Since this somatic typology corresponds to expectations based on data analyzed in a previous investigation, the somatotype method can be considered to be a valuable instrument for quick, preliminary constitutional typings.

Expression of hemochromatosis in homozygous subjects. Implications for early diagnosis and prevention.

This study looks at expression of genetic hemochromatosis in the homozygous and heterozygous states. Two hundred nine subjects in 40 families with confirmed hemochromatosis and clear evidence of HLA linkage in symptomatic individuals were studied prospectively for up to 24 yr. The study group consisted of 40 probands, 51 subjects sharing two HLA haplotypes with affected relatives (putative homozygotes), 98 putative heterozygotes, and 20 putative normal homozygotes. Forty-eight of 51 subjects predicted to be homozygous showed increased hepatic iron stores as assessed by liver biopsy and quantitative phlebotomy. If not evident initially, this developed in 1-8 yr. In the 3 subjects predicted by HLA typing to be homozygous but in whom there was no progressive iron accumulation, results of studies using another chromosome 6 genetic marker (Factor 13 A subunit) were consistent with chromosomal recombination, presumably separating one hemochromatosis allele from the HLA markers. No heterozygous subject developed overt hemochromatosis during the period of follow-up, although 1 showed evidence of iron overload at initial assessment. Genetic recombination is again thought to have separated the hemochromatosis allele from the HLA markers here. The present findings favor a location of the hemochromatosis locus telomeric to HLA-A. It is concluded that, in this population, hemochromatosis is apparently always HLA linked, and homozygous subjects will develop iron overload in the absence of chromosomal recombination or blood loss.

Direct detection of beta thalassemic mutations: use of biotin-labelled allele specific probes.

Mutations at positions beta IVS1-6, beta IVS1-110, and beta 39 of the beta globin gene are responsible for the three most common thalassemic genes in the Mediterranean population. The polymerase chain reaction (PCR) was employed to amplify a 536 base pair segment surrounding this region. Nonradioactive labelling of an oligonucleotide probe, specific for the beta IVS1-110 mutation, was achieved by incorporation of biotin-16-dUTP into a standard 3'-end labelling procedure. This probe was subsequently hybridized with the PCR amplification product and permitted detection of the mutant gene in a homozygous beta thalassemic child by a simple colour detection method using a streptavidin-alkaline phosphatase conjugate and NBT/BCIP (nitroblue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate) substrate. A known cloned mutant gene was similarly detected. Results could be obtained within 48 hr. These findings suggest that such an approach could provide a rapid and specific means for detection of beta thalassemic mutations without the need for radioactive probes.

Prenatal diagnosis of fetal hemoglobin Lepore-Boston disease on maternal peripheral blood.

Molecular diagnosis of hemoglobin (Hb) Lepore-Boston in the fetus was successfully accomplished using maternal blood as a source for fetal cells in three pregnancies at risk for beta-thalassemia/Hb Lepore disease. Taking advantage of the possibility of amplifying Lepore-specific DNA fragments by polymerase chain reaction and of families in which Hb Lepore was inherited by the paternal side, we demonstrated in two cases and excluded in one case the presence of this hemoglobinopathy in the fetus directly on maternal DNA. The diagnosis was concordant with that obtained by traditional approaches in all three cases. Our results unequivocally show that nucleated fetal cells are present in maternal blood during pregnancy, and demonstrate for the first time that prenatal diagnosis of a genetic disease may be feasible without invasive procedures.

[Genetic carrier detection for the Wiskott-Aldrich syndrome using restriction fragment length polymorphism analysis]. / Draagsterschaponderzoek voor het Wiskott-Aldrich-syndroom met behulp van restrictiefragmentlengte-polymorfisme-analyse.

The gene for the Wiskott-Aldrich syndrome, an X-linked immunodeficiency disease, has been mapped between the RFLP markers DXS7 and DXS14 on the short arm of the X-chromosome. Close linkage to these markers permits accurate carrier detection and prenatal diagnosis. In one family with WAS patients in two generations, RFLP analysis was applied to three women at risk. It could be determined with more than 98.5% accuracy that these women were not carriers.

X linked neonatal myotubular myopathy: one recombination detected with four polymorphic DNA markers from Xq28.

A three generation family with X linked myotubular myopathy (MTM1) was studied with several polymorphic markers from the distal long arm of the X chromosome. A recombination between the disease gene and four markers (loci DXS52, DXS134, DXS15, F8C) from the Xq28 cluster was detected. A new polymorphic marker (U6.2) defining the locus DXS304 in the Xq27-28 region proximal to the Xq28 cluster did not show any recombination with MTM1. These results suggest the following order of loci in distal Xq: cen-DXS42-DXS105-(DXS304, MTM1)-(DXS52, DXS134, DXS15, F8C)-tel.

Diagnosis of neurofibromatosis I by using tightly linked, flanking DNA markers.

We tested 132 individuals from 21 families segregating an allele for neurofibromatosis type 1 (NF-1), by using nine RFLPs tightly linked to the NF-1 locus. Family members had requested DNA testing either to determine whether "at risk" children were carrying the NF-1 allele or to determine whether their respective families would be informative for prenatal testing. Predictions about whether a child carries the NF-1 mutation were possible for all 32 at-risk offspring (greater than 98% accuracy based on the recombination estimates currently available for these DNA markers). At least one informative probe was available for all 23 matings in these 21 families; flanking markers were informative for 10 matings. Pairwise analysis showed that several of the polymorphisms were in tight linkage disequilibrium; few recombination events were observed with these markers in the families under study. We conclude that the DNA probes used in this study perform well for diagnostic testing of NF-1 in familial cases. A subset of five probe-enzyme systems (pHHH202/RsaI, p11-3C4.2/MspI, pTH17.19/Bg/II, p11-2C11.7/BamHI, and p11-2F9.8/TaqI) provide reliable linkage information for both clinical testing and prenatal diagnosis.

The use of a genotypic marker to demonstrate clonal dominance during the growth and metastasis of a human breast carcinoma in nude mice.

When a mixture of 11 clones of a human breast carcinoma (MDA-MB-435)--each clone transfected with pSV2neo and identified as having a unique insertion site of the gene--was injected into nude mice, the resulting tumors were found to contain only one clone (Neo 24). This clone, identified by the unique restriction fragments on Southern blot analyses, was also found in metastases recovered from the lungs and lymph nodes of the animals. The individual clones showed no differences in in vitro growth, while in vivo the Neo 24 cells produced the largest tumors. Thus, one explanation for the observed clonal dominance in this study could be the more rapid growth in vivo of the Neo 24 cells. This study illustrates how an introduced selectable gene marker can be used in lineage studies of human tumor cell populations.