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Weaver syndrome (WS), an overgrowth/intellectual disability syndrome (OGID), is caused by pathogenic variants in the histone methyltransferase EZH2, which encodes a core component of the Polycomb repressive complex-2 (PRC2). Using genome-wide DNA methylation (DNAm) data for 187 individuals with OGID and 969 control subjects, we show that pathogenic variants in EZH2 generate a highly specific and sensitive DNAm signature reflecting the phenotype of WS. This signature can be used to distinguish loss-of-function from gain-of-function missense variants and to detect somatic mosaicism. We also show that the signature can accurately classify sequence variants in EED and SUZ12, which encode two other core components of PRC2, and predict the presence of pathogenic variants in undiagnosed individuals with OGID. The discovery of a functionally relevant signature with utility for diagnostic classification of sequence variants in EZH2, EED, and SUZ12 supports the emerging paradigm shift for implementation of DNAm signatures into diagnostics and translational research., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Femur-fibular-ulna (FFU) complex is an unusual, sporadically occurring limb malformation disorder, characterized by a highly variable combination of congenital defects of the femur, the fibula and/or the ulna, which tend to be associated. We report the case of a fetus with FFU complex and additional striking metaphyseal anomalies of the lower limbs and an abnormal chondrocyte organization pattern. To our knowledge this is the first reported case of histologic metaphyseal alterations in association with the FFU complex.

Cohen syndrome is an autosomal recessive disorder with variability in the clinical manifestations, characterized by developmental delay, visual disability, facial dysmorphisms and intermittent neutropenia. We described a cohort of 10 patients affected by Cohen syndrome from nine Italian families ranging from 5 to 52 years at assessment. Characteristic age related facial changes were well documented. Visual anomalies, namely retinopathy and myopia, were present in 9/10 patients (retinopathy in 9/10 and myopia in 8/10). Truncal obesity has been described in all patients older than 6 years (8/8). DNA samples from all patients were analyzed for mutations in COH1 by DHPLC. We detected 15 COH1 alterations most of them were truncating mutations, only one being a missense change. Partial gene deletions have been found in two families. Most mutations were private. Two were already reported in the literature just once. A single base deletion leading to p.T3708fs3769, never reported before, was found in three apparently unrelated families deriving from a restricted area of the Veneto's lowland, between Padova town and Tagliamento river, in heterozygous state. Given the geographical conformation of this region, which is neither geographically or culturally isolated, a recent origin of the mutation could be hypothesized.

We report four cases of subjects with phenotypic abnormalities and mental retardation associated with apparently balanced translocations, two inherited and two de novo, which showed, by molecular analysis, a hidden complexity. All the cases have been analyzed with different molecular techniques, including array-CGH, and in two of them the translocation breakpoints have been defined at the level of base pairs via studies in somatic hybrids containing single derivative chromosomes. We demonstrated that all the translocations were in fact complex rearrangements and that an imbalance was present in three of them, thus accounting for the phenotypic abnormalities. In one case, a Prader-Willi subject, we were not able to determine the molecular cause of his phenotype. This study, while confirming previous data showing unexpected complexity in translocations, further underscores the need for molecular investigations before taking for granted an apparently simple cytogenetic interpretation.

Fluorescent in situ hybridization (FISH) screening of subtelomeric rearrangements has resulted in the identification of previously unrecognized chromosomal causes of mental retardation with and without dysmorphic features. This article reports the phenotypic and molecular breakpoint characterization in a cohort of 12 patients with subtelomeric deletions of chromosome 9q34. The phenotypic findings are consistent amongst these individuals and consist of mental retardation, distinct facial features and congenital heart defects (primarily conotruncal defects). Detailed breakpoint mapping by FISH, microsatellite and single nucleotide polymorphism (SNP) genotyping analysis has narrowed the commonly deleted region to an approximately 1.2 Mb interval containing 14 known transcripts. The majority of the proximal deletion breakpoints fall within a 400 kb interval between SNP markers C12020842 proximally and C80658 distally suggesting a common breakpoint in this interval., (Copyright 2004 Wiley-Liss, Inc.)

We report on a clinical-genetic study of 16 Wolf-Hirschhorn syndrome (WHS) patients. Hemizygosity of 4p16.3 was detected by conventional prometaphase chromosome analysis (11 patients) or by molecular probes on apparently normal chromosomes (4 patients). One patient had normal chromosomes without a detectable molecular deletion within the WHS "critical region." In each deleted patient, the deletion was demonstrated to be terminal by fluorescence in situ hybridization (FISH). The proximal breakpoint of the rearrangement was established by prometaphase chromosome analysis in cases with a visible deletion. It was within the 4p16.1 band in six patients, apparently coincident with the distal half of this band in five patients. The extent of each of the four submicroscopic deletions was established by FISH analyses with a set of overlapping cosmid clones spanning the 4p16.3 region. We found ample variations in both the size of the deletions and the position of the respective breakpoints. The precise definition of the cytogenetic defect permitted an analysis of the genotype-phenotype correlations in WHS, leading to the proposal of a set of minimal diagnostic criteria, which in turn may facilitate the selection of critical patients in the search for the gene(s) responsible for this disorder. We observed that genotype-phenotype correlations in WHS mostly depend on the size of the deletion, a deletion of <3.5 Mb resulting in a mild phenotype, in which malformations are absent. The absence of a detectable molecular deletion is still consistent with a WHS diagnosis. Based on these observations a "minimal" WHS phenotype was inferred, the clinical manifestations of which are restricted to the typical facial appearance, mild mental and growth retardation, and congenital hypotonia., (Copyright 2000 Wiley-Liss, Inc.)

Purpose: Rieger Syndrome (RS) is an autosomal dominant disease, in which Axenfeld's and Rieger's anomalies are associated with typical facial dysmorphism and other extra-ocular findings. Cardiovascular defects are considered an occasional finding in this syndrome., Methods: We describe a RS case in which the typical ocular and dysmorphic features were associated with bicuspid aortic valve. A review of the literature is provided., Results: A total of 15 other cases of Axenfeld's or Rieger's anomaly associated with cardiovascular defects have been reported. In the cases in which the diagnosis of RS could be clinically performed, the cardiac defect mostly involved the outflow tract structures., Conclusion: The hypothesis that this association could be non-coincidental is discussed. The proved genetic heterogeneity of RS, based on clinical and molecular evidence, may suggest that RS is a contiguous gene syndrome or RS with cardiac defect is a separate entity. Finally we suggest a careful cardiological evaluation in RS patients, to assess the real frequency of cardiac defects in this syndrome.

Recent studies demonstrated the existence of a genetically distinct, usually lethal form of the Schwartz-Jampel syndrome (SJS) of myotonia and skeletal dysplasia, which we called SJS type 2. This disorder is reminiscent of another rare condition, the Stüve-Wiedemann syndrome (SWS), which comprises campomelia at birth with skeletal dysplasia, contractures, and early death. To test for possible nosologic identity between these disorders, we reviewed the literature and obtained a follow-up of the only two surviving patients, one with SJS type 2 at age 10 years and another with SWS at age 7 years. Patients reported as having either neonatal SJS or SWS presented a combination of a severe, prenatal-onset neuromuscular disorder (with congenital joint contractures, respiratory and feeding difficulties, tendency to hyperthermia, and frequent death in infancy) with a distinct campomelic-metaphyseal skeletal dysplasia. The similarity of the clinical and radiographic findings is so extensive that these disorders appear to be a single entity. The follow-up observation of an identical and unique pattern of progressive bone dysplasia in the two patients (one with SJS type 2, one with SWS) surviving beyond infancy adds to the evidence in favor of identity. The hypothesis that SWS and SJS type 2 are the same disorder should be testable by molecular methods.

Meckel syndrome (MKS) is a lethal malformation syndrome characterised by posterior meningoencephalocele, polycystic kidneys, fibrotic changes of the liver, and polydactyly. We have previously shown a linkage to chromosome 17q in 17 Finnish Meckel families. In this study we have analysed one Italian, one Austrian (of Turkish origin) and three British MKS families (Caucasian, Pakistani, and Bangladeshi families) for linkage to the MKS locus on chromosome 17q22-q24. We did not observe co-segregation of the disease and marker haplotypes in the Austrian family or in the three British families, of which two represented classical MKS and one a slightly atypical MKS phenotype with longer survival of the patient. In the Italian family the affected and non-affected children did not share the same maternal chromosome and thus this family could represent the same allelic disease as the Finnish MKS families. These results suggest locus heterogeneity in Meckel syndrome--a feature previously suspected based on the highly variable clinical phenotype.

Lateralization defect is a heterogeneous condition with different modes of transmission (autosomal recessive, dominant or X-linked). Here, we report on 3 additional families that contribute to the description of phenotypic anomalies of the autosomal dominant type. Phenotypic anomalies include: lateralization defects, cardiac malformations, diaphragmatic hernia, urologic and neurologic anomalies. We suggest calling this sequence BGD1 for blastogenesis dominant 1 because the deleterious effect probably occurs during blastogenesis and involves not only lateralization but other defects as well.

We report on a family in which 3 sibs were affected with conductive deafness, bilateral preauricular and commissural lip pits, monolateral branchial fistula, and rib anomalies. On the basis of parental consanguinity, lack of clinical variability and affected subjects of both sexes, this condition seems to be inherited as an autosomal recessive trait. We suggest that these findings comprise a new autosomal recessive entity of branchial, auricular and costal anomalies, for which we suggest the acronym BOC (branchio-oto-costal) syndrome.

Ten patients with inverted duplication of 8p (inv dup 8p) were studied with cytogenetic, biochemical and molecular techniques. The duplication for the region 8p12-p22 was always associated with a deletion of the locus D8S7 (mapped in 8p23.1) as demonstrated with the probe pSW50 by both in situ hybridization and Southern blot. Restriction fragment length polymorphisms detected by probes pSW50 (1 case) and by pG2LPL35 (locus LPL) (two cases) were informative as to a maternal origin of the anomaly. The activity of glutathione reductase, whose gene maps in the duplicated region at 8p21.1, was increased in all patients. The recognizable phenotype of inv dup 8p includes neonatal hypotonia, prominent forehead, large mouth with everted lower lip, abnormally shaped large ears, brain malformations and severe mental retardation. Our findings indicate that the chromosome rearrangement is homogeneous at least for the presence of the deletion and support the hypothesis of a common mechanism of origin.

We describe an epidemiological and clinical study of Clinical Anophthalmia in a population of consecutive live and stillborns enrolled in a hospital based registry of congenital malformations in Northeast Italy during the period from 1981 to 1989; 22 cases were detected among 368,256 births yielding a birth prevalence of 0.60 per 10,000 (95% CI 0.34-0.84); 20 cases were associated with at least one other major malformation. Malformation syndrome, association, or sequence was diagnosed in 13, while a non-recognizable multiple defect pattern was observed in 7/20 (35%). A chromosomal anomaly was present in eight syndromic cases. No significant trend over time, nor space or time clusters, were detected. As most CAn cases are associated with other anomalies recognizable by ultrasound, a decreasing trend in its prevalence at birth is expected in the future.

This report concerns 2 unrelated patients with apparent CHARGE association and a chromosome abnormality, resulting from different unbalanced familial translocations involving chromosomes 2 and 18 in one family, and chromosomes 3 and 22 in the other. Although the identification of two different chromosome abnormalities might be due to chance, the observation of a long arm deletion of chromosome 22 in patients 2 and of the frequent coexistence of CHARGE association and DiGeorge anomaly raise the possibility of a contiguous gene syndrome in at least some CHARGE cases.

A boy presenting with an incomplete form of the acrocallosal syndrome is described. The syndrome shows clinical variability and it is stressed that none of the components is constant and facial dysmorphism is not always characteristic.

We describe three patients (one female and two males in a sibship of 11) with mandibuloacral dysplasia. Only eight families have been reported previously, and of these, four were of Italian origin. The phenotypic spectrum of the condition is delineated and its variability is stressed. The observation of three affected members of both sexes with normal parents supports the hypothesis of autosomal recessive inheritance. The reasons for the high frequency of the condition in Italy are discussed; a local selective advantage for heterozygotes and founder effect might be involved.

A family with popliteal pterygium syndrome is reported: two children presented a mild form of the syndrome, while their mother exhibited full expression of the gene. Only 11 families with 29 affected members and 25 sporadic cases have been published. This malformation syndrome is inherited in an autosomal dominant pattern, but environmental factors or genetic heterogeneity cannot be excluded in sporadic occurrences. The variability of expression is discussed and a comparison with previously published familial cases is made: minor anomalies, if present in relatives of patients with full gene expressions, are as helpful in making the diagnosis as are major abnormalities. Careful evaluation of the proband's family is essential for diagnosis and subsequent genetic counselling.

Chromosome analysis of a 15-day old boy with multiple malformations revealed a partial deletion 12(p11;p13).

A 5, 9-12-year-old with trisomy 12 pdue to a maternal reciprocal translocation adjacent 1 segregation is presented. Comparison of his phenotype with that of other patients reported in the literature confirm the existence of a trisomy syndrome.