An unbalanced de novo translocation t(18;22) leading to a severely malformed liveborn girl with 18p- syndrome is described. Using the chromosomal in situ suppression (CISS) hybridization technique on 4-year-old G-banded chromosome preparations, it could be demonstrated that the translocation chromosome is composed of the long arm including the centromere of a chromosome 22 and the long arm of a chromosome 18. Consequently, the patient described here has lost the short arm including the centromere of chromosome 18. The possibility of restudying cytogenetically unsolved cases in clinical cytogenetics using older G-banded chromosome preparations with the fluorescence in situ hybridization techniques is pointed out.

We report on a newborn female patient with a de novo pure partial duplication of 7q. The clinical features are compared with those of 19 cases from the literature with pure partial duplication of different segments of 7q. Conventional cytogenetic investigation led to the diagnosis of duplication of bands q21.3 to q35. This was confirmed by chromosome painting and by fluorescence in situ hybridization with different YAC probes from the duplicated region.

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. © 1996 Wiley-Liss, Inc.

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.

We report on two severely mentally retarded male children of consanguineous parents who seem to be affected by an identical syndrome. The main physical anomalies are typical facial stigmata with a broad nasal bridge, a bulbous nose, upward slanting palpebral fissures, microretrognathia, low hair line, and large ears with an incompletely developed upper helix. In addition, both brothers had hypospadias type II, limb contractures, and delayed bone age. One child had a bilateral cleft lip with cleft palate and cryptorchidism, and developed scoliosis during adolescence. The other had bilateral inguinal hernias and strabismus. Chromosome analysis showed a normal karyotype in both. The striking similarity between the brothers, the dissimilarity to other known syndromes, and the parental consanguinity argue in favour of a new, hitherto undescribed, possibly autosomal recessive syndrome.

This report concerns two patients with clinical features typical for tetrasomy 18p syndrome. Chromosomal analysis revealed a male karotype in both cases, with an additional small metacentric marker chromosome, putatively an i(18p). Fluorescent in situ hybridization with a chromosome 18‐specific paint confirmed that the marker chromosome consisted of chromosome 18 material in both cases.

Clinical, cytogenetic and molecular studies were performed in three patients with Wolf-Hirschhorn syndrome (WHS). In all cases the altered chromosome 4 appeared to be the result of a de novo deletion. Cytogenetic investigations located the breakpoint at 4p15.3 and 4p13. With cytogenetic methods it was not possible to decide whether these deletions were terminal or interstitial. DNA methods also failed to define a distal breakpoint within the 4p16.3 region which might have indicated an interstitial deletion. According to the literature, the paternal chromosome 4 is preferentially deleted in most patients with WHS. DNA analysis with polymorphic markers out of the 4p16.3 region revealed that in two of the cases reported here the deleted segment was of paternal and in one case of maternal origin.

A rare BrdU-sensitive fragile site, designated FRA12C*RQ24.2 has a relatively high frequency in the normal population. It can be demonstrated in a heterozygous and homozygous condition. There is no evidence that a phenotypic abnormality is associated with the expression of this site. A comparison with the fragile site FRA10B*RQ25.2 has revealed common features with FRA12C*RQ24.2.

We report on genetic counseling and investigations in 36 families with inherited balanced translocations ascertained in different ways, with special regard to the completeness and reasons for incompleteness of family investigation. Quantitative evaluation of the results of cytogenetic investigations shows that non‐directive genetic counseling was very effective in many families. Yet, in most of the families (34) genetic counseling and investigation remained incomplete in the sense that not all living potential translocation carriers could be counseled or investigated or that the origin of a fresh mutation could not be established by a normal karyotype in the parents of a carrier. Only in seven families could nearly all living potential carriers be counseled and investigated. The most frequent reason for incompleteness was the impossibility of transmitting or refusal to transmit information about the genetic risks to relatives (21 families), whereas direct rejection of investigation by a counseled individual was a rather rare event (18 adults). Families ascertained because of an unbalanced child seem to be more willing to transmit genetic information to relatives than families ascertained in other ways. Non‐directive genetic counseling gave us an insight into the emotional problems arising during counseling of translocation families.

Ring (20) chromosomal mosaicism defined by two cell lines (one normal and the other with the ring) has been demonstrated in lymphocyte and fibroblast cultures from three members of a family through two generations. Two carriers of the ring chromosome were affected and showed the typical signs of r(20) syndrome including mental retardation, microcephaly, behavioral disorders, and epilepsy. The epilepsy is characterized by complex partial seizures sometimes evolving secondarily into generalized tonic-clonic seizures and is poorly controlled by or resistant to medical treatment. The mother of the two patients, also a carrier of ring (20) chromosomal mosaicism, was clinically and phenotypically normal and did not exhibit any signs of epilepsy. Lymphocyte and fibroblast cultures from the most severely affected sib, the proband, contained the highest percentage of cells with ring (20) chromosome and revealed the greatest instability of the ring. Though it is assumed that the ring (20) chromosome arose from terminal breakage and reunion in both arms, no loss of genetic material could be documented cytogenetically. Yet the question arises of how ring chromosomal mosaicism can be passed on. One explanation might be that a chromosome 20 predisposed to terminal lesions or breaks is transmitted from the mother to her offspring. Inherited instability of this type might lead to de novo formation of the ring.

A BrdU-requiring fragile site, fra(12)(q24.2), on human chromosome 12 of some individuals is reported. This fragile site is inherited in a Mendelian codominant fashion and does not seem to be associated with any physical or mental abnormality in carriers. It was mostly observed as a chromatid gap: no acentric fragments, triradials or deleted chromosomes were found. The fra(12)(q24.2) was expressed in 34%–48% of metaphases in lymphocyte cultures from carriers when BrdU and FdU were added 6.5 h before harvest, while the expression ranged between 5% and 20% when the cultures were treated with BrdU alone. The fra(12)(q24.2) represents the second BrdU-requiring rare fragile site described on human chromosomes.

Missing iris combined with debility and incidence of Wilms' tumor seem to be a complex syndrome which appears in 1:100,000 people. It is caused by an interstitial deletion on the short arm of chromosome no. 11. We refer to a patient who developed end-stage renal failure caused by a focal-segmental nephrosclerosis. He underwent renal transplantation because chronic hemodialysis was impossible due to his lack of compliance. The deletion of chromosome 11 could be recognized by chromosomal analysis after transplantation. An aniridia-Wilms' tumor association (AWTA) with following focal segmental nephrosclerosis could be diagnosed.

Missing iris combined with debility and incidence of Wilms' tumor seem to be a complex syndrome which appears in 1:100,000 people. It is caused by an interstitial deletion on the short arm of chromosome no. 11.

Durch Verkürzung des Interferrikums auf einen äußerst schmalen Schlitz steigt die Feldstärke zwischen den Polen eines Magneten stark an. Es ist uns gelungen, eine Lichtquelle für Gasentladung herzustellen, die einen nur 0,4 mm weiten Schlitz zwischen den Magnetpolen erfordert gegenüber bisher 4 mm. Die Feldstärke steigt dadurch bei unverändert normaler Strombelastung unseres Elektromagneten von 38500 auf 50100 Gauß. Die Auswertung von Zeeman-Effekt-Aufnahmen des Argonspektrums der neuen Lichtquelle bei 50100 Gauß führt keineswegs nur zu zahlenmäßig genaueren Ergebnissen, sondern zeigt die Erschließung eines weiten Gebietes bisher unauflösbarer Zeeman-Effekte an. Die Methode ist auf alle Gasspektra anwendbar.

Neuere Untersuchungen über die Hyperfeinstruktur der Wismutbogenlinien und ihren Zeemaneffekt, welche die früheren Ergebnisse ergänzen und bestätigen. Bemerkungen über das Termschema des Wismuts. Intensitäten in den Hyperfeinmultipletts. „Verbotene“ Komponenten im Paschen — Back — Effekt der Hyperfeinstrukturen.

Die Zeemaneffekte der Wismutlinien in starkem Feld bestätigen die in einem vorangehenden Aufsatz der Verfasser gegebene Auffassung der Hyperfeinstrukturen von Bi als sehr enge Multiplettkombinationen, welche durch ein Kernmoment hervorgerufen werden; die Größe des mechanischen Kernimpulsmoments läßt sich mittels des Zeemaneffektes zu\(4\tfrac{1}{2} \cdot \frac{h}{{2\pi }}\) bestimmen. Die Zeemaneffekte selbst bilden zugleich eine erstmalige experimentelle Bestätigung der Landéschen Theorie der Feinstrukturen im Paschen-Back-Effekt.

Aus den Hyperfeinstrukturen von Wismutlinien kann man eine Anzahl von Termaufspaltungen ableiten, diese bilden eine schöne Bestätigung der Thorsenschen Termordnung des Bi. An die empirisch bestimmten Termaufspaltungen werden einige theoretische Betrachtungen über den wahrscheinlichen Ursprung dieser Feinstrukturen und ihre Quantenzahlen geknüpft.