Molecular basis of choroideremia (CHM): mutations involving the Rab escort protein-1 (REP-1) gene.

Choroideremia (CHM) is an X-linked recessive eye disease that results from mutations involving the Rab escort protein-1 (REP-1) gene. In 18 patients deletions of different sizes have been found. Two females suffering from CHM were reported to have translocations that disrupt the REP-1 gene.

Mutation spectrum in the CHM gene of Danish and Swedish choroideremia patients.

The recent isolation of the complete open reading frame of the choroideremia (CHM) gene and the characterization of the exon-intron boundaries has paved the way to mutation detection in patients with classical choroideremia. We have performed mutation screening in patients from 15 Danish and Swedish families by using Southern blot hybridization and the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) technique. Causative mutations in the CHM gene were detected in at least 12 families, indicating that a substantial part of the mutations can be identified by this approach.

Prenatal exclusion of choroideremia.

We performed prenatal testing to predict the inheritance of choroideremia (CHM) using a linked polymorphic DNA marker, DXS95. DNA analysis of chorionic villi at the 12th week of pregnancy indicated that the allele at risk had not been passed from the heterozygous mother to the fetus. This prenatal exclusion of choroideremia was confirmed by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis.

Detection and characterization of point mutations in the choroideremia candidate gene by PCR-SSCP analysis and direct DNA sequencing.

By making use of positional cloning strategies we recently isolated a candidate gene for choroideremia (CHM), which is transcribed in retina, choroid, and/or retinal pigment epithelium. The gene contains an open reading frame that is structurally altered in 10 CHM patients with sizable deletions and in a female patient with a balanced translocation involving the Xq21 band. Employing PCR-SSCP analysis and direct DNA sequencing we have now detected and characterized different point mutations in five patients with CHM.

Cloning of the breakpoints of a deletion associated with choroidermia.

In order to characterize a previously described submicroscopic deletion encompassing (part of) the choroideremia (tapetochoroidal dystrophy: TCD) gene, we have cloned a 10.5-kb EcoRI fragment from the patient's DNA; this fragment carries the junction between both deletion endpoints ("junction fragment"). The distal portion of this fragment defines a new marker within, or just distal to, the TCD gene.

Validity of cytogenetic analyses from trophoblast tissue throughout gestation.

Cytogenetic findings in the Münster Chorionic Villi Sampling (CVS) program are presented after 1,184 first trimester transcervical samplings and 131 second and third trimester placentacenteses. In the first trimester series the abnormality rate is low (2.4%) in patients with only an age-dependent aneuploidy risk.

[Immunotherapy following habitual abortion in paternal chromosome translocation].

In a 41-year-old VII-gravida, I-para, the husband's reciprocal translocation of the chromosomes 1 and 18 as well as a partial identity of the marital partner in the HLA-system may have been the underlying causes for five abortions. In the 7th pregnancy, a prenatal chromosome analysis was performed as well as an immunotherapy with paternal lymphocytes, when uterine bleeding occurred. After termination of bleeding, the pregnancy continued without any complication.

[Fatal re-infarct in pregnancy].

We report on the third pregnancy of a 41-year-old patient with familial hypercholesterolemia. After preceding angina pectoris symptoms she had her first myocardial infarction at an age of 37. Thereafter she had no complaints under medicinal and dietary treatment.

Rapid karyotyping for prenatal diagnosis in the second and third trimesters of pregnancy.

Direct chromosome preparations were performed on placental villi obtained by ultrasound-guided needle aspiration between 18 and 37 weeks of pregnancy in 53 patients. The sampling yielded a sufficient amount of tissue with a maximum of two, and in most cases one, insertions. Placental biopsy is easily performed in cases of severe oligohydrammnios, where fetal blood sampling is usually more difficult.

A sex cord stromal tumour in a woman with XO/XX/XXX-mosaicism.

We describe a postmenopausal woman with 45,XO/46,XX/47,XXX mosaicism who presented with a Sertoli-Leydig cell tumour and a past history of habitual abortion. The cytogenetic finding is discussed in relation to the etiology of the tumour and of the recurrent abortions.

Feto-maternal transfusion after chorionic villus sampling. Evaluation by maternal serum alphafetoprotein measurement.

The alphafetoprotein (AFP) concentration in maternal serum was determined before and after chorionic villus sampling (CVS). A significant increase of 20% or more in the pre-CVS level was noted immediately after sampling in 59% of 837 pregnancies indicating some degree of feto-maternal haemorrhage. The increase in the AFP concentration in maternal serum was correlated with the weight of the tissue sample but not with the number of sampling attempts.

Deletion of the DXS165 locus in patients with classical choroideremia.

Using various probes from the Xq21 region which is known to carry the choroideremia (tapetochoroideal dystrophy, TCD) locus, we have screened the DNAs from eight unrelated male choroidermia patients for microdeletions. In two of these patients, but not in any of 45 males tested as controls, lack of hybridization signals with probe plbD5 suggested a deletion encompassing the DXS165 locus and (part of) the TCD gene. Absence of additional clinical features in these patients and the fact that two closely linked, and probably flanking, TCD markers (DXYS1 and DXS72) are not deleted may indicate that the physical distance between the DXS165 locus and the TCD gene is small.

C-band polymorphisms of chromosome 9: quantification by Ce-bands.

C-band polymorphisms of chromosome 1 can be quantified by Ce bands visualized using oblique epi-illumination. In this paper the polymorphic region of chromosome 9, including variants such as 9qh+, inversions, and translocations, was analyzed in a total of 1860 chromosomes from 20 individuals and 8 fetuses. In this sample we found between zero and five Ce bands on 9q and between zero and four Ce bands on 9p with a maximum of five Ce bands per chromosome.

[Rett syndrome--case report].

We report on a 13 years old girl with Rett syndrome (autism, dementia, ataxia and loss of purposeful hand use in girls). The Rett syndrome is unexpectedly frequent (1:15,000 in 1-14 years old girls). The diagnosis is based solely upon clinical development observation.

Three cases of 45,X/46,XYnf mosaicism. Molecular analysis revealed heterogeneity of the nonfluorescent Y chromosome.

Three patients with 45,X/46,XYnf mosaicism were investigated by Southern hybridization using both X- and Y-specific DNA probes. Our patients seem to be hemizygous for the X chromosomal loci tested. Single-copy and low-copy repeated Y chromosomal sequences assigned to the short arm, centromere, and euchromatin of the long arm have been detected in our patients, suggesting the Y chromosomal origin of the marker chromosome both in male and female cases studied.

An improved darkfield-illuminator for direct surface imaging of chromosomes.

An improved darkfield-illumination system for comfortable and convenient use of oblique incidence epi-illumination is described. The illuminator employs a new means for altering the position of the aperture diaphragm allowing a subtle adjustment of both the direction and the angle of the incident light bundle. The efficacy of this device for surface imaging is demonstrated in human chromosomes.

Estimating frequency of Kallmann syndrome among hypogonadic and among anosmic patients.

The frequency of Kallmann syndrome (hypogonadotropic hypogonadism and anosmia, HHA) was estimated in patients presenting with hypogonadism and patients with anosmia. Of 791 hypogonadal males 19 had HHA. The frequency of HHA was about 1:25 (n = 8/189) in outpatients questioned about their sense of smell, about 1:50 (n = 11/579) in patients whose blood samples were sent to us for chromosome analysis, and about 1:30 (n = 19/605) in males with hypogonadism and 46,XY chromosomes.

Inv dup (15): prenatal diagnosis and postnatal follow-up.

A de novo inv dup (15) was diagnosed at amniocentesis. No physical abnormalities were detected after birth. The boy developed severe mental and motor retardation, which became obvious at 16 months of age.

Choroideremia-locus maps between DXS3 and DXS11 on Xq.

Choroideremia is a progressive tapetochoroidal dystrophy with X-linked transmission leading frequently to blindness in affected males. The choroideremia-locus (TCD) has recently been assigned to the long arm of the X chromosome by linkage to polymorphic DNA markers. In order to further define the location of the gene defect, two families segregating for choroideremia were examined for DNA restriction fragment length polymorphisms.

[Chromosome studies of chorionic villi: experiences following 118 diagnostic interventions].

We summarize our experience with chorionic villi cultures. Cell growth and chromosome analysis were successful in all cases. A significant admixture of maternal cells in chorionic villi cultures can be excluded by comparison of fluorescence polymorphisms between maternal and embryonic chromosomes.

[Prenatal diagnosis from chorionic villi: results in Münster].

We report on our experience with the first 46 diagnostic chorionic villi samplings in Münster. A new echogenic plastic catheter is used. The observed abortion rate is in accordance with international experience.