Genetics of resistance to wheat leaf rust, stem rust, and powdery mildew in Aegilops sharonensis

Aegilops sharonensis (Sharon goatgrass) is a wild relative of wheat and a rich source of genetic diversity for disease resistance. The objectives of this study were to determine the genetic basis of leaf rust, stem rust, and powdery mildew resistance in A. sharonensis and also the allelic relationships between genes controlling resistance to each disease. Progeny from crosses between resistant and susceptible accessions were evaluated for their disease reaction at the seedling and/or adult plant stage to determine the number and action of genes conferring resistance. Two different genes conferring resistance to leaf rust races THBJ and BBBB were identified in accessions 1644 and 603. For stem rust, the same single gene was found to confer resistance to race TTTT in accessions 1644 and 2229. Resistance to stem rust race TPMK was conferred by two genes in accessions 1644 and 603. A contingency test revealed no association between genes conferring resistance to leaf rust race THBJ and stem rust race TTTT or between genes conferring resistance to stem rust race TTTT and powdery mildew isolate UM06-01, indicating that the respective resistance genes are not linked. Three accessions (1644, 2229, and 1193) were found to carry a single gene for resistance to powdery mildew. Allelism tests revealed that the resistance gene in accession 1644 is different from the respective single genes present in either 2229 or 1193. The simple inheritance of leaf rust, stem rust, and powdery mildew resistance in A. sharonensis should simplify the transfer of resistance to wheat in wide crosses.

Resistance of Sharon Goatgrass (Aegilops sharonensis) to Fungal Diseases of Wheat

Sharon goatgrass (Aegilops sharonensis) is a wild relative of wheat that is native to Israel and Lebanon. The importance of A. sharonensis as a source of new resistance genes for wheat warrants additional research on the characterization of accessions for economically important genes. Thus, the objectives of this study were to evaluate a collection of A. sharonensis accessions for resistance to seven important fungal diseases of wheat and assess the phenotypic diversity of the germplasm for disease reaction. The frequency of resistance in A. sharonensis was highest to powdery mildew (79 to 83%) and leaf rust (60 to 77%). Resistance to stem rust also was common, although the percentage of resistant accessions varied markedly depending on the pathogen race-from 13% to race TTTT to 72% to race QCCJ. The frequency of resistance was intermediate to stripe rust (45%) and low to tan spot (15 to 29%) and spot blotch (0 to 34%). None of the A. sharonensis accessions was resistant to Fusarium head blight. Many of the accessions tested exhibited heterogeneous reactions (i.e., had both resistant and susceptible plants) to one or more of the diseases, suggesting that heterozygosity may be present at some resistance loci. Substantial variation was observed in the level of diversity to individual diseases because Shannon's Equitability index ranged from 0.116 (for Fusarium head blight) to 0.994 (for tan spot). A high level of diversity was found both between and within collection sites. Moreover, differences in the geographic distribution of resistant accessions were observed. For example, accessions from northern Israel generally were less diverse and less resistant to leaf rust and stripe rust than accessions from more southern locations. Four A. sharonensis accessions were highly resistant to most of the diseases evaluated and may provide a source of unique resistance genes for introgression into cultivated wheat.

Audiometric and imaging characteristics of distal renal tubular acidosis and deafness

Objective:

Primary distal renal tubular acidosis with sensorineural hearing loss is a rare autosomal recessive disease, usually caused by mutations in the ATP6V1B1 gene. The aim of this study was to characterise the phenotype of this disease, with emphasis on the auditory findings, in a cohort of Israeli children.

Study design:

Prospective study of five children, from three unrelated families, with distal renal tubular acidosis and bilateral sensorineural hearing loss, with mutations in the ATP6V1B1 gene.

Methods:

The following were collected from patients' medical records: biochemical and renal data, age at distal renal tubular acidosis diagnosis, and age at hearing loss. Hearing loss progression as well as current hearing status were assessed, and high resolution computed tomography of the temporal bone was performed. All patients underwent genetic testing.

Results:

Four patients were diagnosed with distal renal tubular acidosis before the age of six months and one at 24 months. All had the classical findings of low blood pH and inappropriately high urine pH. Hearing loss was diagnosed between the ages of three months and two years. The hearing loss was bilateral, asymmetrical and progressive, occasionally with a conductive component. Two children underwent cochlear implantation, at ages 10 and 15 years. High resolution computed tomography, performed in four patients between the ages of 2.5 and 15 years, showed bilaterally enlarged vestibular aqueducts. This was the only radiological abnormality in the inner ear in all cases. A different mutation in the ATP6V1B1 gene was found in each family.

Conclusion:

Several types of mutations in the ATP6V1B1 gene may cause distal renal tubular acidosis and sensorineural hearing loss. Patients display a typical progressive type of hearing loss and have enlarged vestibular aqueducts, with no other abnormalities being observed on imaging.

Spatio-temporal genetic variation in populations of wild emmer wheat, Triticum turgidum ssp. dicoccoides, as revealed by AFLP analysis

Genetic structure of natural populations of wild crop relatives has been the subject of many studies. Yet, most of them focused on the assessment of spatial genetic diversity, while information on long-term variation, affected by yearly changes, has been considered only in few cases. The present study aimed therefore, to estimate the spatio-temporal genetic variation in populations of wild emmer wheat, the progenitor of domesticated wheat, and to assess the contribution of spatial versus temporal factors to the maintenance of genetic variation in a population. Single spikes were collected in the years 1988 and 2002 from plants that grew in the same sampling points, from six different habitats in the Ammiad conservation site, Eastern Galilee, Israel. Seeds were planted in a nursery and DNA was extracted from each plant and analyzed by the AFLP method. Fourteen primer combinations yielded 1,545 bands of which 50.0 and 48.8% were polymorphic in the years 1988 and 2002, respectively. Genetic diversity was much larger within populations than between populations and the temporal genetic diversity was considerably smaller than the spatial one. Nevertheless, population genetic structure may vary to some degree in different years, mainly due to fluctuations in population size because of yearly rainfall variations. This may lead to predominance of different genotypes in different years. Clustering the plants by their genetic distances grouped them according to their habitats, indicating the existence of genotype-environment affinities. The significance of the results in relation to factors affecting the maintenance of polymorphism in natural populations is discussed.

Peak bone mass in patients with phenylketonuria

OBJECTIVE

Several studies have suggested a compromised bone mass in phenylketonuria patients but most reported on heterogeneous or small patient groups. Our aim was to evaluate peak bone mass in adult PKU patients and to relate BMD to nutritional parameters.

PATIENTS AND METHODS

BMD was measured by dual-energy x-ray absorptiometry in 31 adult PKU patients (18 female), mean age 25 +/- 5.3 years. Nutritional intake was calculated based on food diaries. Diet adherence was determined based on patients' report.

RESULTS

Mean blood phenylalanine (Phe) concentration was 968 +/- 526 micromol/L (16 +/- 8.7 mg/dl). Eight patients (32.2%) met the recommended blood Phe concentration of <726 micromol/L (<12 mg/dl), and there was no significant difference in Phe concentrations between diet-adherent and non-adherent patients. Osteopenia was detected in 11 patients (38.7%), while osteoporosis was detected in 2 patients (6.5%). No correlation was found between BMD and age, blood minerals, Phe, vitamin D and alkaline phosphatase levels, calcium and protein intake, body mass index, and body fat percentage.

CONCLUSIONS

Peak bone mass is decreased in PKU patients. Possible explanations include long-standing dietary deficiency in protein, calcium, vitamin D or trace elements, or a primary defect in bone turnover inherent to the disease itself. Our data do not favour any of these hypotheses. Further studies are needed to elucidate the cause of low bone density in PKU patients.

Infusion of platelets transiently reduces nucleoside overload in MNGIE

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is caused by thymidine phosphorylase (TP) deficiency, which leads to toxic accumulations of thymidine (dThd) and deoxyuridine (dUrd). In this work, we report that infusion of platelets from healthy donors to patients with MNGIE restored transiently circulating TP and reduced plasma dThd and dUrd levels, suggesting that treatments to achieve permanent restoration of circulating TP such as allogeneic stem cell transplantation or gene transfer might be therapeutic.

Spore dimensions of Puccinia species of cereal hosts as determined by image analysis

Digital image analysis was used to measure dimensions of spores produced by Puccinia coronata, P. graminis, P. hordei, P. recondita, P. striiformis and P. triticina. Included were teliospores, basidiospores, urediniospores and, except for P. striiformis, pycniospores and aeciospores. Length, width and projection area of spores were measured with NIH Image or Scion software. By using limits on size, spores were automatically selected and measured, except for teliospores, which required manual elimination of the pedicel and separation of images of adhering spores. Length and width were determined as the major and minor axes of the best fitting ellipse for each spore. This procedure gave values for length and width close to results obtained with an ocular micrometer. Projection area was determined as the number of pixels within spore boundaries multiplied by the area represented by each pixel, giving values that are not feasible to obtain accurately with an ocular micrometer. Of the species studied, spores of P. recondita had the largest dimensions, P. triticina had the smallest. The rank of the six species based on increasing width, length or projection area was almost the same, using each spore type except pycniospores. Generally, differences of 5% in a given spore dimension between two species were significant. Differences between species were greater with basidiospores and aeciospores than with other spore types. Teliospores were unique in that length and width were negatively correlated, resulting in less variation in area than in length or width. The results indicate that image analysis is useful for measuring spore dimensions, that projection area of spores is a useful added parameter for characterizing rust species and that dimensions of teliospores, basidiospores, aeciospores and urediniospores each are potentially useful for differentiating species.

Resistance to Leaf Rust, Stripe Rust, and Stem Rust in Aegilops spp. in Israel

In all, 1,323 single plant accessions of Aegilops bicornis, A. kotschyi, A. longissima, A. ovata, A. searsii, A. sharonensis, A. speltoides, and A. variabilis collected from 18 regions in Israel and 2 adjacent regions in Lebanon and Egypt were evaluated for leaf rust (Puccinia triticina) and stripe rust (P. striiformis) resistance in field plots and for seedling resistance to leaf rust and stem rust (P. graminis f. sp. tritici) in greenhouse tests. Nearly all accessions of A. speltoides were highly resistant to leaf rust, stripe rust, and stem rust. A. longissima and A. ovata were highly resistant to stripe rust, whereas A. bicornis and A. kotschyi were highly susceptible. A. searsii was highly susceptible to stem rust, but 24 to 51% of accessions of A. bicornis, A. longissima, A. ovata, and A. variabilis were resistant to stem rust. Except for A. ovata and A. speltoides, more than 95% of the Aegilops accessions were susceptible to leaf rust caused by P. recondita alternating on Anchusa spp. Only Aegilops ovata was susceptible to P. recondita from Echium spp. A. bicornis, A. koschyi, and A. searsii were highly susceptible as seedlings to common wheat leaf rust caused by P. triticina. Most accessions of A. variabilis and about half of the accessions of A. longissima had good seedling resistance to P. triticina. Few accessions of A. ovata showed seedling resistance to the P. triticina population in Israel, but 30% were resistant to U.S. isolates. In field tests, A. bicornis showed high susceptibility to common wheat leaf rust, but more than 90% of the accessions of the other Aegilops spp. developed little or no leaf rust on adult plants. The Aegilops spp. in Israel and adjoining countries provide a rich and varied source of rust resistance for wheat breeding.

Leaf Rust and Stem Rust Resistance in Triticum dicoccoides Populations in Israel

A total of 742 single plant accessions of Triticum dicoccoides were collected from 26 locations in Israel. All accessions were evaluated for leaf rust (Puccinia triticina) resistance in field plots at Tel Aviv, and subsets of 284 and 468 accessions were tested in the greenhouse in Tel Aviv and St. Paul, MN, respectively, for seedling resistance to leaf rust; 460 accessions were also tested for seedling resistance to stem rust (Puccinia graminis f. sp. tritici) in St. Paul. One accession was highly resistant to leaf rust in seedling tests in Tel Aviv, and 21 others had moderately susceptible to moderately resistant seedling resistance. Four accessions were highly resistant to leaf rust in seedling tests in St. Paul, and 11 were resistant to at least one stem rust race. Adult resistance to leaf rust was more common than seedling resistance among the accessions; 21 accessions had less than 25% leaf rust severity in field plots compared with 80 to 90% severity for highly susceptible accessions. Most of the accessions with effective adult plant resistance came from two nearby locations in Upper Galilee, a region where populations of T. dicoccoides are most extensive and genetically diverse. These accessions may provide valuable new partial resistance genes for durable protection against leaf rust in cultivated wheat.

Virulence associations in oat crown rust

ABSTRACT Isolates of Puccinia coronata obtained from natural populations of Avena sterilis in Israel, winter oat (A. sativa) cultivars in Texas, and spring oat cultivars in the Northern Plains states of Minnesota, North Dakota, and South Dakota were analyzed for significance of pairwise virulence associations. Isolates from all three regions were tested on 25 oat lines with single P. coronata (Pc) genes for crown rust resistance from A. sterilis and one line with a Pc gene from A. sativa. Isolates from Israel were tested also on 11 Iowa backcross lines with undesignated crown rust resistance genes from A. sterilis. Four associated virulence groups were identified from significant positive virulence associations that were consistent across all three regions. Group 38 included virulence to Pc-38, Pc-39, Pc-55, Pc-63, and Pc-71; group 45 included virulence to Pc-45, Pc-46, Pc-48, Pc-52, Pc-54, and Pc-57; group 58 included virulence to Pc-35, Pc-40, Pc-58, and Pc-59; and group 61 included virulence to Pc- 36, Pc-51, Pc-56, Pc-60, and Pc-61. Virulence to Pc-70 showed the strongest association to virulences in group 38 but also showed significant association with virulence to Pc-45, Pc-35, and Pc-58. Virulences in group 61 were consistently negatively associated with virulences in group 38 in each region. In Israel, virulences to five of the Iowa lines showed positive associations to virulences in group 61 and negative associations to virulences in groups 38 and 45. Close similarity of reactions of nearly all isolates to Pc-39, Pc-55, and Pc-71 suggest that these genes may be identical or nearly identical alleles.

Genetic Variation and Virulence on Lr26 in Puccinia triticina

ABSTRACT The genetic relationships between isolates of Puccinia triticina virulent on wheat with the Lr26 resistance gene were studied. The diversity within and between isolates of P. triticina from Israel, Europe, and the United States was determined by virulence on near-isogenic Thatcher lines and by random amplified polymorphic DNA. According to the molecular markers, isolates that were virulent on Lr26 had diversity levels similar to those of Lr26 nonpathogenic isolates. Distances between subpopulations of isolates virulent and avirulent on Lr26 varied and were unrelated to the Lr26 virulence phenotype. Cluster analysis suggested four groups, three of which were closely associated with the geographical origin of the isolates-Israel, the United States, and Europe. All four groups included both Lr26 virulent and avirulent pathotypes. The results showed that Lr26 virulent rust pathotypes are as genetically dissimilar as the rest of the population. The cluster analysis showed that the rust population in Israel includes at least two different subpopulations, both of which contain Lr26 virulent and Lr26 avirulent isolates.

Morphology, life cycle biology, and DNA sequence analysis of rust fungi on garlic and chives from california

ABSTRACT In the late 1990s, commercial garlic fields in California (CA) were devastated by an outbreak of rust caused by Puccinia allii. We compared collections of the pathogen from garlic (Allium sativum) and chives (A. schoenoprasum) in central CA and Oregon (OR) to collections from garlic and leek (A. porrum and A. ampeloprasum) in the Middle East. Teliospores from the CA and OR collections were smaller in length, width, and projected cross-sectional area compared with collections from the Middle East. CA and OR collections had a shortened life cycle, in which pycnia and aecia were not formed. Germinating teliospores produced a two-celled promycelium, resulting in two basidiospores, each initially with two nuclei, indicating that this rust was homothallic. In addition, the morphology of the substomatal vesicles was different between the CA-OR (fusiform) and the Middle Eastern (bulbous) collections. DNA sequence analysis of the nuclear ribosomal internal transcribed spacer region showed that the CA and OR rust collections formed a well-supported cluster distinct from the Middle Eastern and European samples. These results suggest that the rust on garlic and chives in CA and OR is a different species than the rust fungus on garlic and leek in the Middle East.

Patterns of Virulence in Natural Populations of Puccinia coronata on Wild Oat in Israel and in Agricultural Populations on Cultivated Oat in the United States

ABSTRACT Crown rust (Puccinia coronata) in indigenous populations of Avena sterilis has been cited as an example of stability of wild pathosystems that consist of natural mixtures of resistance and virulence. This study confirmed that virulence/avirulence polymorphisms in P. coronata on A. sterilis in Israel are highly diverse and that super races do not dominate. Isolates of P. coronata from Israel in 1991 to 1996 were polymorphic for virulence to 35 of 36 differential oat lines with resistance genes from A. sterilis. On average, isolates of P. coronata were more highly virulent to differentials with Pc genes from A. sterilis accessions from Israel than to differentials with Pc genes from other countries. Isolates from Israel also were more virulent on average to 10 additional differentials with Pc genes derived from A. sativa than to differentials with Pc genes from A. sterilis. Frequencies of virulence were usually higher in collections of P. coronata from Israel than in collections from cultivated oat in the United States, even though several of the Pc genes in the differentials have been used extensively in American oat cultivars. Mean virulence complexity of P. coronata from eight regions of Israel was not correlated with the distribution of resistance among collections of A. sterilis from previous surveys in the same areas, probably because pathogen migration between regions within Israel is sufficient to obscure effects of selection locally.

The influence of space in genetic-environmental relationships when environmental heterogeneity and seed dispersal occur at similar scale

We tested the importance of microenvironmental topographic parameters as predictors of emmer wheat genetic variation using three classes of single-locus (or at most several-loci) genetic markers (allozymes, glutenins, and qualitative traits) and two classes of markers of polygenic inheritance (phenological and morphological traits). Canonical correspondence analysis (CCA) and redundancy analysis (RDA) detected a significant effect of spatially structured environmental variation on genetic differences between plants for allozymes, glutenins, and quantitative morphological and phenological traits. However, after removing a spatial component of variation in partial CCA and partial RDA, the relationship of the remaining environmental variation with these genetic markers could be explained by chance alone, allowing us to rule out microniche topographic specialization in emmer wheat. Topographic autocorrelation exhibited a certain degree of similarity with genetic marker autocorrelation, indicating similar scales of environmental heterogeneity and seed flow. The detected population genetic structure agrees with one expected under isolation by distance as a result of limited gene flow. A negative relationship of genetic similarity with the logarithm of distance between plants was detected for both molecular markers and quantitative traits, which differed in the strength but not the pattern of association.

CTNS mutations in African American patients with cystinosis

Cystinosis, an autosomal recessive lysosomal storage disorder, is rarely diagnosed in African Americans. The disease results from mutations in the gene CTNS; at least 55 such mutations have been reported. By far the most common is a 57,257-bp deletion of Northern European origin encompassing most of the CTNS gene. We performed mutation analysis on DNA from four African American patients with cystinosis. In one individual with classical, nephropathic cystinosis, we identified a new molecular defect, i.e., a homozygous GT-->CC substitution at the +5 position of IVS 5 of CTNS (IVS 5+5 GT-->CC). The out-of-frame splicing of exon 5 creates a null allele consistent with the patient's severe phenotype. Two patients were heterozygous and one homozygous for the common 57-kb deletion allele, reflecting the admixture of African and Northern European gene pools in North America. The two African Americans heterozygous for the 57-kb deletion were also hemizygous for a 928G-->A change, associated with ocular or nonnephropathic cystinosis. These two individuals are the only known African Americans with ocular cystinosis. We conclude that the diagnosis of cystinosis should be entertained in African Americans with symptoms of the disease, and that mutation analysis for the 57-kb deletion should be considered in this group of patients.

A new genetic isolate of gray platelet syndrome (GPS): clinical, cellular, and hematologic characteristics

Gray platelet syndrome (GPS) is a disorder characterized by thrombocytopenia and large platelets that lack alpha granules and their contents. We describe two siblings with GPS who are members of a Moslem Bedouin genetic isolate. The children, an 8-year-old girl and a 5-year-old boy, had characteristic pale blue platelets lacking alpha granules on electron microscopy. Platelet aggregation studies were normal. The girl underwent a bone marrow aspiration and biopsy which showed mild myelofibrosis and extensive emperipolesis, i.e., the passage of other hematopoietic cells through megakaryocytes. Both children lacked high-molecular-weight multimers of von Willebrand factor (vWF) and had reduced activity and antigens of vWf. Platelet activation was approximately normal when ADP was employed as agonist, but significantly impaired using the thrombin receptor-activating peptide (TRAP). These findings are explained in light of the mechanism of action of each agonist. In addition, we propose that the emperipolesis was caused by increased P-selectin in megakaryocytes, and resulted in release of fibroblastic growth factors, explaining the myelofibrosis. The detailed description of these cases provides a basis for future differentiation of the various types of GPS, and for our current attempts to isolate the gene causing GPS in this genetic isolate.

Characterization of the murine gene corresponding to human Hermansky-Pudlak syndrome type 3: exclusion of the Subtle gray (sut) locus

Hermansky-Pudlak syndrome (HPS) consists of oculocutaneous albinism and a bleeding diathesis due to absent platelet dense bodies. In addition to exhibiting considerable phenotypic variation, this autosomal recessive disorder displays locus heterogeneity. One causative gene is HPS1, coding for a protein of unknown function and resulting in HPS-1 disease, common in northwest Puerto Rico. A second HPS-causing gene is ADTB3A, coding for the beta3A subunit of adaptor complex-3 (AP-3, a coat protein complex) and resulting in HPS-2 disease. Each of these HPS subtypes has a murine counterpart, specifically pale ear for HPS-1 and pearl for HPS-2. Recently, the HPS3 gene, responsible for HPS-3 disease in a genetic isolate of central Puerto Rico, was isolated and characterized. Its location on human chromosome 3q24 suggested that the mouse model corresponding to HPS-3 disease might be subtle gray. To examine this possibility, we determined the mouse HPS3 sequence, its genomic organization, and its amino acid sequence, which shares 95.8% identity with the human protein. We demonstrated that the subtle gray mouse produces a normal size and amount of HPS3 mRNA and has an entirely normal sequence in every exon and intron/exon boundary. Furthermore, subtle gray exhibits a normal contingent of platelet dense bodies. Together, these data eliminate subtle gray as a murine model for HPS-3 disease and suggest that other mouse models be examined.

Mutation of a new gene causes a unique form of Hermansky-Pudlak syndrome in a genetic isolate of central Puerto Rico

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder characterized by oculocutaneous albinism and a storage pool deficiency due to an absence of platelet dense bodies. Lysosomal ceroid lipofuscinosis, pulmonary fibrosis and granulomatous colitis are occasional manifestations of the disease. HPS occurs with a frequency of one in 1800 in north-west Puerto Rico due to a founder effect. Several non-Puerto Rican patients also have mutations in HPS1, which produces a protein of unknown function. Another gene, ADTB3A, causes HPS in the pearl mouse and in two brothers with HPS-2 (refs. 11,12). ADTB3A encodes a coat protein involved in vesicle formation, implicating HPS as a disorder of membrane trafficking. We sought to identify other HPS-causing genes. Using homozygosity mapping on pooled DNA of 6 families from central Puerto Rico, we localized a new HPS susceptibility gene to a 1.6-cM interval on chromosome 3q24. The gene, HPS3, has 17 exons, and a putative 113.7-kD product expected to reveal how new vesicles form in specialized cells. The homozygous, disease-causing mutation is a large deletion and represents the second example of a founder mutation causing HPS on the small island of Puerto Rico. We also present an allele-specific assay for diagnosing individuals heterozygous or homozygous for this mutation.

Hermansky-Pudlak syndrome and Chediak-Higashi syndrome: disorders of vesicle formation and trafficking

The rare autosomal recessive metabolic disorders Hermanky-Pudlak syndrome (HPS) and Chediak-Higashi syndrome (CHS)share the clinical findings of oculocutaneous albinism and a platelet storage pool deficiency. In addition, HPS exhibits ceroid lipofuscinosis and CHS is characterized by infections and an accelerated phase. The two disorders result from defects in vesicles of lysosomal lineage. Of the two known HPS-causing genes, HPS1 has no recognizable function, while ADTB3A codes for a subunit of an adaptor complex responsible for new vesicle formation from the trans-Golgi network. Other HPS-causing genes are likely to exist. The only known CHS-causing gene, LYST, codes for a large protein of unknown function. In general, HPS appears to be a disorder of vesicle formation and CHS a defect in vesicle trafficking. These diseases and their variants mirror a group of mouse hypopigmentation mutants. The gene productsinvolved will reveal how the melanosome, platelet dense body, and lysosome are formed and trafficked within cells.

Mutation analysis of the MCM gene in Israeli patients with mut(0) disease

Three novel mutations (IVS8+3a --> g, N219Y, and E414X) were identified in 6 unrelated patients with mut(0) methylmalonic aciduria. The presence of a wild-type along with rearranged fragments in homozygotes for the IVS8+3a --> g mutation may contribute to their later age of onset (3-11 months of age). Nonetheless, delayed onset was not associated with better neurological outcome and prolonged survival. The large number of undiagnosed dead sibs in most families suggests that the disease is largely underdiagnosed in this region.

Molecular cloning and characterization of human VPS18, VPS 11, VPS16, and VPS33

In multicellular organisms, the delivery of proteins to lysosomes is essential. Many of the genes necessary for this process have first been identified by their requirement for vacuolar delivery in yeast. A subset of these genes, the four class C vps genes, is necessary for the delivery of endocytic and biosynthetic cargo in yeast, and also in Drosophila. Here, we describe the sequence and expression pattern of four human homologs of these genes. This initial molecular description of these four genes is an important step towards their evaluation as candidate genes that may be involved in the pathogenesis of Hermansky-Pudlak syndrome-related diseases.

Pulmonary dysfunction in adults with nephropathic cystinosis

OBJECTIVE

To characterize the pulmonary dysfunction in patients with nephropathic cystinosis after renal transplantation.

DESIGN

Cross-sectional analysis of consecutive adult patients.

PATIENTS

Twelve adult, nephropathic cystinosis patients and 3 adult, ocular, nonnephropathic cystinosis patients admitted to the National Institutes of Health Clinical Center.

RESULTS

The 12 nephropathic cystinosis patients (age range, 21 to 40 years) showed an extraparenchymal pattern of restrictive lung disease, with inspiratory and expiratory dysfunction. Specifically, the mean FVC was 58% of predicted, the mean FEV(1) was 57% of predicted, and the mean total lung capacity was 66% of predicted, while the mean residual volume was normal. Furthermore, the mean maximal inspiratory pressure for the eight patients tested was 40% of predicted, and the mean maximal expiratory pressure was 26% of predicted. Two patients died of respiratory insufficiency. All the patients had lived at least 17 years, while lacking compliant cystine-depleting therapy with oral cysteamine. Seven patients had a conical chest, restricting excursion, and 10 of the 12 patients had evidence of the myopathy that typifies late cystinosis. In fact, the severity of pulmonary disease correlated directly with the severity of myopathy in our group of 12 patients. In contrast, the lung parenchyma was essentially normal, as gauged by chest radiographs and CT scans of the lung. The three patients with nonnephropathic cystinosis displayed entirely normal pulmonary function.

CONCLUSION

The distal myopathy characteristic of nephropathic cystinosis results in an extraparenchymal pattern of restrictive lung disease in adults who have not received long-term cystine depletion. Whether or not oral cysteamine therapy can prevent this complication remains to be determined.