Lujan-Fryns syndrome (mental retardation, X-linked, marfanoid habitus)

The Lujan-Fryns syndrome or X-linked mental retardation with marfanoid habitus syndrome is a syndromal X-linked form of mental retardation, affecting predominantly males. The prevalence is not known for the general population. The syndrome is associated with mild to moderate mental retardation, distinct facial dysmorphism (long narrow face, maxillary hypoplasia, small mandible and prominent forehead), tall marfanoid stature and long slender extremities, and behavioural problems. The genetic defect is not known. The diagnosis is based on the presence of the clinical manifestations. Genetic counselling is according to X-linked recessive inheritance. Prenatal testing is not possible. There is no specific treatment for this condition. Patients need special education and psychological follow-up, and attention should be given to diagnose early psychiatric disorders

Piecing together the problems in diagnosing low-level chromosomal mosaicism

Low-level somatic chromosomal mosaicism, which usually arises from post-zygotic errors, is a known cause of several well defined genetic syndromes and has been implicated in various multifactorial diseases. It is, however, not easy to diagnose, as various physical and technical factors complicate its identification

Prenatal diagnosis of congenital diaphragmatic hernia not amenable to prenatal or neonatal repair: Brachmann-de Lange syndrome

Brachmann-de Lange syndrome (BDLS) is a variable multiple congenital anomaly syndrome that occasionally includes congenital diaphragmatic hernia (CDH). CDH per se is commonly diagnosed antenatally and has been corrected with increasing success in utero and by neonatal repair with extracorporeal membrane oxygenation (ECMO). In utero repair requires normal karyotype as well as the absence of other lethal anomalies. Postnatal repair in combination with ECMO has resulted in improved neonatal outcome and has been recommended in all cases not having in utero repair. We describe a fetus diagnosed with a diaphragmatic hernia at 18 weeks of gestation in a woman whose only other pregnancy has been a 16 week abortus diagnosed with Fryns syndrome (FS). FS is a lethal, variable congenital anomaly syndrome that includes CDH, which is thought to contribute to the lethality of the syndrome. In utero repair was considered, but rejected because of the position of the liver and suspected FS. The Patients elected to carry the pregnancy to term. Postnatal repair with ECMO was considered; however, the infant died at several hours of age because of severe pulmonary hypoplasia, being considered ineligible for ECMO. The diagnosis of BDLS was made at autopsy and suggests that the first case may, in fact, have been BDLS. In spite of recent success in the repair of CDH both in et ex utero, CDH in association with BDLS is likely lethal, and women with fetuses diagnosed antenatally with CDH and BDLS should be counseled as such. © 1993 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38260/1/1320470717_ftp.pd

A case of intercommunity lethal aggression by chimpanzees in an open and dry landscape, Issa Valley, western Tanzania

Intercommunity (lethal) aggression is a familiar component of the behavioural repertoire of many forest-dwelling chimpanzee (Pan troglodytes) communities. However, until now, the absence of intercommunity attacks - including killings - in communities that live in open, mosaic environments has supported hypotheses of reduced resource competition in drier habitats, and informed referential models of early hominin social dynamics in a similar habitat. In June 2020, we observed the first instance of intercommunity lethal aggression, a male-committed infanticide, by the Issa chimpanzee community, which live in a savannah-mosaic habitat in the Issa Valley, western Tanzania. The carcass was recovered by researchers after it was abandoned by the attackers. Here, we give a detailed account of the events leading up to and including the infanticide, and contextualise our observations with what has been described for other chimpanzee communities. Notably, in contrast to the majority of reported intercommunity infanticides, the infant male victim was castrated (and not cannibalised), making this the youngest reported castration. This observation of intercommunity aggression disproves its hypothesised absence in savannah-dwelling chimpanzees, which by extension, has implications for early hominin evolution. We suggest that the near absence of observations of intercommunity aggression in savannah chimpanzee communities is most likely due to the lack of long-term study communities, and in some cases geographic isolation. We hypothesise that food-rich areas within a habitat with otherwise widely distributed food sources may select for intense intercommunity aggression despite the low population density characteristic of savannah communities. Anecdotes such as this add to the comparative database available on intercommunity killings in chimpanzee society, improving our ability to draw inferences about their evolutionary significance

Fine mapping of X-linked clasped thumb and mental retardation (MASA syndrome) in Xq28

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66121/1/j.1399-0004.1994.tb04016.x.pd

Meiotic errors followed by two parallel postzygotic trisomy rescue events are a frequent cause of constitutional segmental mosaicism

Structural copy number variation (CNV) is a frequent cause of human variation and disease. Evidence is mounting that somatic acquired CNVs are prevalent, with mosaicisms of large segmental CNVs in blood found in up to one percent of both the healthy and patient populations. It is generally accepted that such constitutional mosaicisms are derived from postzygotic somatic mutations. However, few studies have tested this assumption. Here we determined the origin of CNVs which coexist with a normal cell line in nine individuals. We show that in 2/9 the CNV originated during meiosis. The existence of two cell lines with 46 chromosomes thus resulted from two parallel trisomy rescue events during postzygotic mitoses

The Computation of Surface Lightness in Simple and Complex Scenes

The present thesis examined how reflectance properties and the complexity of surface mesostructure (small-scale surface relief) influence perceived lightness in centresurround displays. Chapters 2 and 3 evaluated the role of surface relief, gloss, and interreflections on lightness constancy, which was examined across changes in background albedo and illumination level. For surfaces with visible mesostructure (“rocky” surfaces), lightness constancy across changes in background albedo was better for targets embedded in glossy versus matte surfaces. However, this improved lightness constancy for gloss was not observed when illumination varied. Control experiments compared the matte and glossy rocky surrounds to two control displays, which matched either pixel histograms or a phase-scrambled power spectrum. Lightness constancy was improved for rocky glossy displays over the histogram-matched displays, but not compared to phase-scrambled variants of these images with equated power spectrums. The results were similar for surfaces rendered with 1, 2, 3 and 4 interreflections. These results suggest that lightness perception in complex centre-surround displays can be explained by the distribution of contrast across space and scale, independently of explicit information about surface shading or specularity. The results for surfaces without surface relief (“homogeneous” surfaces) differed qualitatively to rocky surfaces, exhibiting abrupt steps in perceived lightness at points at which the targets transitioned from being increments to decrements. Chapter 4 examined whether homogeneous displays evoke more complex mid-level representations similar to conditions of transparency. Matching target lightness in a homogeneous display to that in a textured or rocky display required varying both lightness and transmittance of the test patch on the textured display to obtain the most satisfactory matches. However, transmittance was only varied to match the contrast of targets against homogeneous surrounds, and not to explicitly match the amount of transparency perceived in the displays. The results suggest perceived target-surround edge contrast differs between homogeneous and textured displays. Varying the mid-level property of transparency in textured displays provides a natural means for equating both target lightness and the unique appearance of the edge contrast in homogeneous displays

Duplications of the critical Rubinstein-Taybi deletion region on chromosome 16p13.3 cause a novel recognisable syndrome

Background The introduction of molecular karyotyping technologies facilitated the identification of specific genetic disorders associated with imbalances of certain genomic regions. A detailed phenotypic delineation of interstitial 16p13.3 duplications is hampered by the scarcity of such patients. Objectives To delineate the phenotypic spectrum associated with interstitial 16p13.3 duplications, and perform a genotype-phenotype analysis. Results The present report describes the genotypic and phenotypic delineation of nine submicroscopic interstitial 16p13.3 duplications. The critically duplicated region encompasses a single gene, CREBBP, which is mutated or deleted in Rubinstein-Taybi syndrome. In 10 out of the 12 hitherto described probands, the duplication arose de novo. Conclusions Interstitial 16p13.3 duplications have a recognizable phenotype, characterized by normal to moderately retarded mental development, normal growth, mild arthrogryposis, frequently small and proximally implanted thumbs and characteristic facial features. Occasionally, developmental defects of the heart, genitalia, palate or the eyes are observed. The frequent de novo occurrence of 16p13.3 duplications demonstrates the reduced reproductive fitness associated with this genotype. Inheritance of the duplication from a clinically normal parent in two cases indicates that the associated phenotype is incompletely penetrant

The function and evolution of child-directed communication

Funding: Writing this article was supported by the National Centre of Competence in Research (NCCR) Evolving Language, Swiss National Science Foundation Agreement 51NF40 180888 for JS, CF, FW, KZ, CPvS, SWT and SS. SWT was additionally funded by Swiss National Science Foundation grant PP00P3_198912.Humans communicate with small children in unusual and highly conspicuous ways (child- directed communication (CDC)), which enhance social bonding and facilitate language acquisition. CDC-like inputs are also reported for some vocally learning animals, suggesting similar functions in facilitating communicative competence. However, adult great apes, our closest living relatives, rarely signal to their infants, implicating communication surrounding the infant as the main input for infant great apes and early humans. Given cross-cultural variation in the amount and structure of CDC, we suggest that child-surrounding communication (CSC) provides essential compensatory input when CDC is less prevalent—a paramount topic for future studies.Publisher PDFNon peer reviewe