It has been claimed that Williams syndrome (WS) children have an unusual command of language reminiscent of "cocktail party speech." An analysis of the spoken language of 43 school-age WS children showed a subgroup (37% of the sample) who produced significantly more speech, more complex utterances, more social phrases and clichés, and more complex communicative functions, when compared with the rest of the WS group. Thus, hyperverbal speech is not a consistent manifestation of the syndrome. The speech of 20 WS children was compared with the speech of mentally handicapped control children. There were no differences in the quantity of language produced, in its grammatical complexity, or in the range and frequency of communicative functions that were expressed. But more of the WS children had an over-familiar manner and used more adult vocabulary and social phrases. It is suggested that their speech appears so different from the speech of other mentally handicapped children primarily because of these vocabulary and stylistic differences, and because of the contrast between their verbal abilities and their more impaired visuo-spatial and motor skills.

During a 7-year-period (1980-1986) trisomy 21 was confirmed in 635 cases (257 males and 278 females). There were 611 cases of trisomy 21 (96.2%), 12 of different translocations (1.9%), 9 of mosaicism (1.4%), and 3 with nonclassical karyotypes (0.5%). The frequency of chromosome aberrations in our study is compared to that of major world-wide cytogenetic surveys comprising 17,738 Down syndrome cases. These surveys showed that regular trisomy 21 constitutes 92.9%, translocations 4.3%, mosaicism 2.2%, and nonclassical karyotypes 0.5%.

Down syndrome (DS) individuals are known to be predisposed to develop leukemia and their lymphocytes are highly sensitive to the induction of chromosome aberrations by X-rays. A study was conducted to identify the chromosome breakpoints and to evaluate whether site specificity for chromosome breakage and rearrangement may exist which may explain the predisposition phenomenon. DS lymphocytes at the G1 phase of the cell cycle were irradiated with 300, 450, and 600 rad of X-rays. Cells were harvested after 3 days in culture and 193 G-banded karyotypes were analyzed to identify the induced chromosome abnormalities. Out of 273 breakpoints identified, 122 were involved in the formation of stable chromosome rearrangements and 151 in the formation of unstable abnormalities. The Poisson analysis of these breakpoints demonstrated that 16 chromosome bands located in chromosomes 1, 3, 7, 12, 17, 19 and X were preferentially involved in breakage and rearrangement (P less than 0.05). These 16 bands are also found to be locations of "cancer breakpoints," oncogenes, or fragile sites. Many abnormal cells were observed to carry stable chromosome rearrangements only. Therefore, these cells are presumed to be compatible with survival and to be "initiated" in the transformation process. We propose that similar stable and site-specific chromosome rearrangements may exist in proliferating cells in DS individuals after exposure to clastogens and that this abnormality predisposes them to develop leukemia.

The epidemiology of Down syndrome (DS) was studied in the area which is covered by our registry of congenital malformations. For each of the 139 new DS cases which were ascertained during the period 1979 to 1987 more than 50 factors were studied and compared to those from control infants. The prevalence of DS was 1.17%; 3.6% of the DS cases were stillbirths and 14.4% were induced abortions. Karyotypes were obtained in 137 cases of which all but 7 were 47, + 21, 4 were mosaics (2.8%), and 5 had translocations (3.6%). Interchromosomal effect was a question in 3 cases. The most common types of associated malformations were cardiac anomalies (44.6%) and intestinal atresia. We did not observe seasonality or time/space clusters in spite of the Chernobyl nuclear accident. No paternal age effect was demonstrated. In our material the first-born infants were at lower risk of DS than the later born. Five percent of the mothers of DS had 2 previous spontaneous abortions (controls 2.8%). At birth, the DS infants measured less and their head circumference was lower than in control infants. Weight of placenta was also lower than in control infants. In our material there were 7.9% of consanguineous marriages (P = .010). The pregnancies of the DS children were often complicated by threatened abortions; 6.4% of the mothers of the DS children were diabetic (P = .069). For all other factors studied no statistically significant difference with respect to controls could be demonstrated.

The incidence of Down syndrome (DS) families where one of the parents is an heterozygous carrier of pericentric inversion of the heterochromatic region of chromosome 9-inv(9) (qh) - was determined in 3 independent groups of 100 families each. The total number of 17 such families found in the sample is significantly greater than the expected number of 5.73 for a sample of non-DS families of equal size. Consequently, the statistical association of the presence of inv (9) (qh) in one parent with the birth of a DS offspring, and the correlative 3-fold increased risk of a DS child for such families, seem to be demonstrated. A study of the origin of nondisjunction, using restriction fragment length polymorphism (RFLP) segregation analysis with a sufficient number of chromosome 21 specific probes, has provided complete information in 7 of 8 available families. Although the statistical interpretation of the results is not straightforward, due to the small size of the sample, the observed data do not contradict the assumption that the presence of inv (9) (qh) in a parent increases, by a factor of about 3, the chance that the offspring will inherit an extra chromosome 21 from that parent. Nevertheless, gathering further data appears desirable because stronger evidence would have relevance both for clinical implications and for the understanding of the function of heterochromatin, particularly with respect to meiotic and mitotic processes.

Ever more frequent and closer involvement by clinical geneticists and counselors in the prenatal assessment of development mandates a better understanding of all stages of human ontogeny, but especially those of earliest development during which most of the lethal and all of the gross, multiple and complex defects of morphogenesis arise. Because of the phenomenon of universality, i.e., identical molecular inductive mechanisms involved in the process of embryonic pattern formation in all vertebrates, experimental animals indeed are a most valuable approach to an understanding of the causal and formal aspects of development and are beginning to forge essential, strong bonds between molecular biologists and clinicians in a mutually supportive discipline of developmental biology. However, to grieving parents of a stillborn fetus with, say, Pentalogy of Cantrell, sirenomelia or otocephaly, mouse data offer little comfort or reassurance about recurrence; thus, it is imperative to make ever more effective a science of human teratology (sensu lato) with participating reproductive geneticists, obstetricians, neonatologists, ultrasonographers, pediatric/fetal pathologists, cytogeneticists and pediatric geneticists to generate the diagnostic, pathogenetic and causal data necessary to counsel and to comfort the parents. Few molecular data exist on causes of blastogenetic defects in humans; however, the phenomenon of parsimony, whereby the same "morphogenetic" molecule, say, sonic hedgehog (SHH), is "deployed" simultaneously or sequentially during the morphogenesis (and even the histogenesis) of several/many embryonic primordia, makes it likely that a genetic/epigenetic disturbance of such an inductive system will have multiple effects on blastogenetic, organogenetic and perhaps also histogenetic events in the embryo. If causally defined, such a pattern of anomalies constitutes pleiotropy, and the embryo/fetus can be said to have a syndrome. If cause is unknown, the presumption of pleiotropy is less certain, and the fetus/infant may be said to have an "association" with low empiric recurrence risk.

Abstract The original article to which this Erratum refers was published in American Journal of Medical Genetics (2002) 108(1) 1–6

We report on the extremely rare occurrence of a stable dicentric duplication-deletion chromosome 14 in a viable offspring with multiple malformations and developmental delay. This abnormality was derived from a maternal paracentric inversion in the long arm of chromosome 14. Both classical and molecular cytogenetic techniques were used to perform the chromosomal investigation of this structural abnormality. The immunofluorescent labeling of centromeric proteins shows only one functional centromere on the rearranged chromosome 14. The present observation confirms that paracentric inversions may lead to stable recombinant chromosomes.

Emphasis has been placed in this special issue on solid tumors, because cytogenetic and molecular genetic progress in the leukemias and lymphomas has far outstripped that in solid tumors— as is evident from the article in this issue by Chen and Sandberg [2002] and the extensive literature in this field. Hence, our aim is to indicate a few of the problems underlying similar studies in solid tumors and the challenges they present. In this Seminars in Medical Genetics dealing with the cytogenetic and molecular aspects of cancer and leukemia, an attempt has been made to bring the reader’s attention to the up-to-date findings in some of the common cancers and leukemias. Space limitations prevent us from presenting articles on numerous other conditions, some of which we refer to or list here in Tables I–III. Most of these conditions (Table I) are associated with complex cytogenetic and molecular changes akin to those of certain of the cancers discussed in this issue (see the article by Sandberg on bladder cancer, for example) [Sandberg, 2002]. Although the genetic changes in these tumors may follow an orchestrated stepwise process, the causative change and subsequent genetic anomalies responsible for the development of the full tumor biological picture (including invasiveness and metastases) have not been established with rigor [Sandberg,