Localization of the gene for Wieacker-Wolff syndrome in the pericentromeric region of the X chromosome

The Wieacker-Wolff syndrome (WWS, MIM* 314580), first described clinically in 1985, is an X-linked recessive disorder. In earlier studies, linkage between the WWS gene and DXYS1 at Xq21.2 and DXS1 at Xq11 as well as AR at Xq12 was reported. Here we report on a linkage analysis using highly polymorphic, short terminal repeat markers located in the segment from Xp21 to Xq24. No recombination between the WWS locus and ALAS2 or with AR (z = 4.890 at theta = 0.0) was found. Therefore, the WWS locus was assigned to a segment of approximately 8 cM between PFC (Xp11.3-Xp 11.23) and DXS339 (Xq11.2-Xq13).

Rare combination of Becker muscular dystrophy and Klinefelter's syndrome in one patient

Becker muscular dystrophy (BMD) was diagnosed in a male patient with Klinefelter's syndrome (47, XXY karyotype). The BMD was confirmed by (i) immunohistological methods and Western blotting, showing decreased quantity of dystrophin in muscle biopsy specimen and (ii) molecular genetic analysis which demonstrated a homozygous deletion of exons 45-47 within the dystrophin gene on both X-chromosomes. The same deletion was found on one of the X-chromosomes in the patient's mother. It can be deduced therefore that Klinefelter's syndrome in this patient is most likely due to a non-disjunctional error which occurred either during the second maternal meiotic division or during early postzygotic mitotic divisions.

[The importance of counseling in the context of prenatal diagnosis]

Counseling plays a central role of the utmost importance in the doctor-patient/client relationship in medical genetics. Historically, its development may be described as a paradigm shift from eugenics via preventive medicine to a more psychosocial understanding as a communication process, which aims at individually bearable, autonomous decisions. The widely accepted conception of non-directiveness in genetic counseling has implications for the rights of patients and clients as well as for the duties of those offering and performing genetic diagnosis and counseling. In the context of prenatal diagnosis, genetic counseling has its special role as a framework to prevent ethically unacceptable automatism and to safeguard the interests of the individual patient/client. In view of the marked lack of adequate counseling capacities, increasing the potential of prenatal genetic diagnosis requires the development of different, possibly new concepts for counseling in this area.

Enhancement of in vivo adenovirus-mediated gene transfer and expression by prior depletion of tissue macrophages in the target organ

Based on the hypothesis that tissue macrophages present an obstacle for adenovirus (Ad) vector-mediated gene transfer to internal organs, this study evaluated the consequences of transient depletion of Kupffer cells on subsequent transfer of the Ad vector genome and Ad vector-directed gene expression in the livers of experimental animals. Depletion of Kupffer cells in mice by intravenous administration of multilamellar liposomes containing dichloromethylene-bisphosphonate permitted subsequent intravenous administration of an Ad vector to provide a higher input of recombinant adenoviral DNA to the liver, an absolute increase in transgene expression, and a delayed clearance of the vector DNA and transgene expression. These observations suggest that the tissue macrophages pose a significant hurdle to Ad vector-mediated gene transfer and that strategies to transiently suppress macrophage defenses might be useful in enhancing the efficiency of this in vivo gene transfer system.

Innate immune mechanisms dominate elimination of adenoviral vectors following in vivo administration

To evaluate the contribution of the innate immune component of host defense in clearing the genome of adenovirus (Ad) vectors following in vivo administration, the Ad vectors AdCMV.beta gal (expressing beta-galactosidase) or AdCMV.Null (expressing no gene) were administered intravenously to immunocompetent or immunodeficient mice, and the amount of vector genome was quantified in the liver. Strikingly, 90% of vector DNA was eliminated within 24 hr. There was no increase in vector DNA in other tissues over this period, suggesting that rapid clearance of vector genome resulted from local degradation. After 24 hr, vector elimination was slow, with only 9% of the initial amount of vector genome cleared over the subsequent 3 weeks. Importantly, early phase (0-24 hr) elimination of vector DNA was independent of the transgene and similar in immunocompetent and nude animals. These observations suggest two phases of Ad vector elimination: a previously recognized late, immune-related elimination, and the early, innate immune elimination described in the present study. The early phase of vector loss is, by far, the dominant mechanism, an observation that has implications in developing strategies to maintain persistent expression of the newly transferred gene following in vivo gene therapy.

Isochromosome Xq in Klinefelter syndrome: report of 7 new cases

In this collaborative study we report on 2 prenatally and 5 postnatally diagnosed cases with a 47,X,i(Xq),Y chromosomal constitution. Excepting tall stature, the 5 adult patients showed all typical manifestations of Klinefelter syndrome. Taken together with previously reported cases, these data suggest that Klinefelter syndrome with isochromosome Xq has a favorable prognosis with normal mental development, and with normal-to-short stature. The prevalence of this Klinefelter variant is calculated to be between 0.3-0.9% in males with X chromosome polysomies.

Severe mental retardation and macroorchidism without mutation in the FMR1 gene

Only one missense mutation, an Ile304Asn, has been reported in the fragile X gene (FMR1). This mutation is located in the second KH domain of FMR1, and has led to the discovery of the function of the FMR1 gene product as an RNA-binding protein. The patient carrying this mutation has profound mental retardation, macroorchidism, and an "acromegalic" face with prominent supraorbital ridges, enlarged jaw, heavy brow ridges, thick lips, and a broad nose. We have studied the possible involvement of FMR1 in two maternal half-brothers with a phenotype similar to that of the patient with the Ile304Asn mutation. Both brothers had an identical number of CGG repeats in the normal size-range, and shared the same maternal Xq27 haplotype. Southern blot analysis with two overlapping FMR1 cDNA clones, spanning the total FMR1 open reading frame, showed no major deletions, insertions, or gross rearrangements. Single-strand conformation pattern (SSCP) analysis of the KH domains showed no aberrant patterns. The total open reading frame of the FMR1 gene was cloned and sequenced, but no mutation was found. Northern blot analysis showed mRNA in the normal size-range, and immunocytochemistry on individual lymphocytes indicated that FMRP, the protein product of FMR1, was present. In conclusion, it is unlikely that FMR1 plays a role in the phenotype of this patient. Other genes may be responsible for the combination of mental retardation and macroorchidism.

Public education for community care. A new approach

BACKGROUND

The findings from a controlled study of the effect of a public education campaign on community attitudes to mentally ill people are presented.

METHOD

A census of neighbours' attitudes toward mental illness was conducted in two areas before the opening of supported houses for the mentally ill. In one area an educational campaign was conducted. The attitude survey was then repeated in both areas and patients' social contact with neighbours was recorded.

RESULTS

Respondents exposed to the didactic component of the campaign showed only a small increase in knowledge about mental illness but there was a lessening of fearful and rejecting attitudes in the experimental area and not in the control area. Neighbours in the experimental area were more likely to make social contact with both staff and patients. It was social contact which was directly associated with improved attitudes rather than education per se. Patients in the experimental area made contact and even friendships with neighbours whereas those in the control area did not.

CONCLUSIONS

The public education campaign did not lead to significant change in neighbours' knowledge of mental illness. However, their attitudes improved and patients' social integration was enhanced.

Ectopic expression of thyrotropin releasing hormone (TRH) receptors in liver modulates organ function to regulate blood glucose by TRH

Maintenance of blood glucose by the liver is normally initiated by extracellular regulatory molecules such as glucagon and vasopressin triggering specific hepatocyte receptors to activate the cAMP or phosphoinositide signal transduction pathways, respectively. We now show that the normal ligand-receptor regulators of blood glucose in the liver can be bypassed using an adenovirus vector expressing the mouse pituitary thyrotropin releasing hormone receptor (TRHR) cDNA ectopically in rat liver in vivo. The ectopically expressed TRHR links to the phosphoinositide pathway, providing a means to regulate liver function with TRH, an extracellular ligand that does not normally affect hepatic function. Administration of TRH to these animals activates the phosphoinositide pathway, resulting in a sustained rise in blood glucose. It should be possible to use this general strategy to modulate the differentiated functions of target organs in a wide variety of pathologic states.

Community attitudes to mental illness

BACKGROUND

The baseline findings from a controlled study of the effect of a public education campaign on community attitudes to mental illness are presented.

METHOD

A census of attitudes to mental illness was conducted in two areas, prior to the opening of supported houses for the mentally ill. Factor analysis of the Community Attitudes toward the Mentally Ill (CAMI) inventory revealed three components: Fear and Exclusion, Social Control and Goodwill.

RESULTS

The only determinant of Fear and Exclusion was having children. The main determinants of Social Control were social class, ethnic origin, age, having suffered mental illness and having children. The main determinant of Goodwill was educational level. The attitude factors were predictive of respondents' behavioural intentions toward the mentally ill. Respondents with children and non-Caucasians were more likely to object to the mentally ill living in their neighbourhood.

CONCLUSIONS

Any intervention aimed at changing attitudes to mentally ill people in the community should be targeted at people with children and non-Caucasians, as these groups are more likely to object.

Community knowledge of mental illness and reaction to mentally ill people

BACKGROUND

We test the hypothesis that negative attitudes to mentally ill people may be fuelled by a lack of knowledge.

METHOD

A census of knowledge of mental illness was conducted in two areas prior to the opening of long-stay supported houses for the mentally ill in each area. Three attitudinal factors (Fear and Exclusion, Social Control and Goodwill) which had been extracted by factor analysis of the Community Attitudes toward the Mentally Ill (CAMI) inventory (see previous paper) were analysed in respect of their associations with knowledge of mental illness.

RESULTS

Most respondents (80%) knew of somebody who had a mental illness but a substantial proportion of respondents had little knowledge about mental illness. Social Control showed an association with knowledge of mental illness. Groups who showed more socially controlling attitudes (especially those over 50 years old, those of lower social class, and those of non-Caucasian ethnic origin) had less knowledge about mental illness. Regression analysis revealed that when knowledge was taken into account, age had no effect on Social Control, and the effect of social class and ethnic origin was diminished. Respondents with children, who showed more Fear and Exclusion, were not less knowledgeable about mental illness.

CONCLUSIONS

The results support the hypothesis that negative attitudes, especially in older people, are fuelled by a lack of knowledge. Negative attitudes among people with children are not related to a lack of knowledge.

Transcript mapping and processing of mitochondrial RNA in the chlorophyte alga Prototheca wickerhamii

The detailed transcript map of the circular 55328 bp mitochondrial (mt) genome from the colourless chlorophycean alga Prototheca wickerhamii has been determined. On each half of this genome the genes are encoded only on one DNA strand, forming transcriptional units comprising variable numbers of genes. With the exception of four genes coding for ribosomal proteins, transcripts of the three rRNA genes and all protein-coding genes have been detected by both northern analysis and primer extension experiments. Polycistronic transcripts of protein coding and tRNA genes were verified by northern analyses, primer extension and RNAse mapping experiments. The 5' and 3' ends of different RNA species are often located in close proximity to putative stem-loop structures and some 5' termini of mRNAs coincide with the 3' end of tRNAs located immediately upstream. Transcript mapping in a putative promoter region revealed two different possible transcription initiation sites; no significant sequence homology to putative mt promoters from higher plants could be found. In addition, two out of three group I introns residing in the cox1 gene were found to be self-splicing in vitro under reaction conditions developed for related mt introns from a filamentous fungus. Mitochondrial gene expression of P. wickerhamii and of filamentous fungi has several features in common, such as intron splicing and the processing of longer polycistronic transcripts. The similarities in RNA maturation between higher-plant and P. wickerhamii mitochondria are less pronounced, since plants rarely use tRNAs as processing signals for their relatively short mitochondrial co-transcripts.

Clinical course of hypophosphatemic rickets in 23 adults

Twenty-three adult patients (19 females, 4 males) with x-linked hypophosphatemic rickets (HPR) underwent a retrospective evaluation of the clinical course and a clinical examination by a nephrologist, orthopedic surgeon and dentist. Blood and urine analysis, bone density measurements with QCT and DEXA, ultrasonic examination of the kidneys were performed and the patients were asked to fill in a standardized questionnaire on pain and psychosocial rehabilitation. Mean final height was 152.4 cm +/- 8.5 SD in females and 157.3 cm +/- 8.9 SD in males. Decreased joint mobility was seen in all patients, deviations of the normal leg axis in 18/23 patients in spite of 69 correcting osteotomies in the past. Dental (n = 14) and psychosocial problems were associated with inability to work (n = 8). There was a trend that patients with a very low Tp/GFR had a more severe course of the disease. Early therapy with vitamin D metabolites and phosphate had a beneficial effect on growth, bone density and deformations. Eight patients had nephrocalcinosis due to vitamin D and phosphate therapy and had normal kidney function. Four patients had urinary tract abnormalities. We conclude that patients with HPR should receive continuous interdisciplinary care given by nephrologists, orthopedic surgeons, physiotherapists and dentists not only during childhood but also as adults.

"Sero-switch" adenovirus-mediated in vivo gene transfer: circumvention of anti-adenovirus humoral immune defenses against repeat adenovirus vector administration by changing the adenovirus serotype

Recombinant, replication-deficient adenovirus (Ad) vectors have been successfully used to transfer and express the normal human cystic fibrosis transmembrane conductance regulator (CFTR) cDNA in vivo in the respiratory epithelium of experimental animals and humans with cystic fibrosis (CF). Since Ad-directed gene expression wanes over time, repeat administration is necessary to achieve an effective treatment for CF. A major hurdle to such a strategy is the possibility that anti-Ad humoral immunity may prevent gene expression in individuals with pre-existing anti-Ad immunity or following repeat administration. One strategy to circumvent such a problem would be alternating the use of Ad vectors belonging to different subgroups. Neutralizing antibodies developed with the administration of one Ad serotype do not cross-react with an Ad belonging to a second serotype in a manner that blocks infection and gene expression. To test this hypothesis, an immunizing dose of wild-type Ad5 (subgroup C), Ad4 (subgroup E), or Ad30 (subgroup D) was administered intratracheally to experimental animals, followed by an intratracheal administration of a replication-deficient subgroup C-derived vector coding for marker genes (chloramphenicol acetyl transferase or beta-galactosidase) or for the normal human CFTR cDNA. As expected, studies with vectors coding for marker genes or for CFTR cDNA demonstrated that airway administration of a vector does not yield efficient gene transfer, if there has been prior recent airway administration of the same Ad subgroup. In contrast, effective expression from the second administration can be achieved with an adenovirus vector belonging to a subgroup different from the first adenovirus administered. These data support the paradigm of alternating Ad vectors derived from different subgroups as strategy to circumvent anti-Ad humoral immunity, thus permitting the use of Ad vectors as a means to treat the respiratory manifestations of CF.

An analysis of desynchronization between the spontaneously breathing patient and ventilator during inspiratory pressure support

It is common practice to convert patients with acute respiratory insufficiency (ARI) from controlled mechanical ventilation to some form of assisted spontaneous breathing as early as possible. A widely used mode of assisted spontaneous breathing is patient-triggered inspiratory pressure support (IPS). We investigated 11 patients with ARI during weaning from mechanical ventilation using IPS and found that in 9 of these patients, desynchronization between patient and ventilator occurred, ie, that the ventilator did not detect and support all the patients' breathing efforts. Five of these 9 patients displayed severe desynchronization lasting at least 5 min and with less than half of all breathing efforts being supported by the ventilator. We present the analysis of gas flow, volume, esophageal pressure, airway pressure, and tracheal pressure of 1 patient with ARI displaying desynchronization under IPS. Our results imply that desynchronization can occur due to the following: (1) inspiratory response delays caused by the inspiratory triggering mechanisms and the demand flow characteristics of the ventilator; (2) a mismatch between the patient's completion of the inspiration effort and the ventilator's criterion for terminating pressure support; and (3) restriction of expiration due to resistance from patient's airways, endotracheal tube, and expiratory valve. From our analysis, we have made proposals for reducing desynchronization in clinical practice.

Mutations in FGFR1 and FGFR2 cause familial and sporadic Pfeiffer syndrome

Pfeiffer syndrome (PS) is an autosomal dominant skeletal disorder which affects the bones of the skull, hands and feet. Previously, we have mapped PS in a subset of families to chromosome 8cen by linkage analysis and demonstrated a common mutation in the fibroblast growth factor receptor-1 (FGFR1) gene in the linked families. Here we report a second locus for PS on chromosome 10q25, and present evidence that mutations in the fibroblast growth factor receptor-2 (FGFR2) gene on 10q25 cause PS in an additional subset of familial and sporadic cases. Three different point mutations in FGFR2, which alter the same acceptor splice site of exon B, were observed in both sporadic and familial PS. In addition, a T to C transition in exon B predicting a cysteine to arginine substitution was identified in three sporadic PS individuals. Interestingly, this T to C change is identical to a mutation in FGFR2 previously reported in Crouzon syndrome, a phenotypically similar disorder but one lacking the hand and foot anomalies seen in PS. Our results highlight the genetic heterogeneity in PS and suggest that the molecular data will be an important complement to the clinical phenotype in defining craniosynostosis syndromes.

Time constant/volume relationship of passive expiration in mechanically ventilated ARDS patients

Since the adult respiratory distress syndrome (ARDS) lung is known to be inhomogeneous, one could expect an uneven distribution of expiratory time constant during uninterrupted mechanical ventilation. We investigated the time constant/volume relationship of passive expiration, and their modification by external resistive elements. In 12 paralysed intubated ARDS patients, we determined the expiratory time constant (tau E) as a function of the expired volume (VE) during uninterrupted mechanical ventilation. Mean expiratory time was 2.9 +/- 0.3 s (+/- SD). VE was divided into five equal volume slices (portions) and a mean tau E calculated from the expiratory tidal volume/flow curve for each slice. The mean values of tau E for each volume slice did not differ significantly throughout expiration, averaging 690 +/- 218 ms (mean +/- SD of five slices and 12 patients). We show that the flow-dependent resistance of the endotracheal tube (RETT) is mainly responsible for the observed time constant homogeneity. We conclude that in ARDS patients during uninterrupted mechanical ventilation the time constants of passive expiration are markedly modified by the flow-dependent resistance of the endotracheal tube (RETT), and also by the external resistance of tubing and ventilator (REX). RETT and REX render tau E about three times larger than the time constant of the patient's respiratory system alone.

Two unrelated children with developmental delay, short stature and anterior chamber cleavage disorder, cerebellar hypoplasia, endocrine disturbances and tracheostenosis: a new entity?

Two unrelated children with developmental delay, anterior chamber-cleavage disorder, proportionate short stature and striking similarity in facial appearance appear to have an identical syndrome. Peters' plus syndrome has to be considered but additional abnormalities not described in this syndrome and their apparently different facies may be evidence for a hitherto undescribed condition. The further malformations both children have in common are cerebellar hypoplasia, hypothyroidism, tracheostenosis and dislocated hips.

Presymptomatic diagnosis in families with adenomatous polyposis using highly polymorphic dinucleotide CA repeat markers flanking the APC gene

A panel of five multiallelic and highly informative dinucleotide CA repeat markers flanking the APC gene was used for presymptomatic diagnosis of familial adenomatous polyposis coli (FAP). Marker regions were amplified by PCR. DNA fragments were separated by electrophoresis in denaturing polyacrylamide gels and visualised by ethidium bromide staining. Two or more markers were found to be informative in all nine families tested, and all 23 persons at risk could be diagnosed as affected or unaffected by the disease gene, the probability being > 99.9% in 14 cases from six families in which flanking markers were informative. We found no indication for locus heterogeneity of the disease in our sample. The polyposis phenotype and its extracolonic manifestations co-segregated with a distinct haplotype determined by the markers flanking the APC gene. In one family with no remaining living affected members, we could infer the high risk haplotype from genotyping of first degree relatives. The segregation of this haplotype is consistent with the occurrence of CHRPEs in the progeny. In a sporadic case we made use of the typical early extracolonic manifestations of the disease (osteomas, desmoids) to identify the high risk haplotype. We conclude from our experience that indirect genotyping of FAP with this particular panel of closely linked and highly polymorphic microsatellite markers is a rapid, efficient, and highly reliable method for presymptomatic diagnosis of FAP.