Congenital heart defects in the recurrent 2q13 deletion syndrome

The recurrent 2q13 deletion syndrome is a rare genetic disorder associated with developmental delay, cardiac and urogenital malformations, and minor facial anomalies. Congenital heart defects (CHDs) are the most frequent malformations associated with del2q13. Experimental studies in zebrafish suggest that two genes mapping within the 2q13 critical region (FBLN7 and TMEM87B) could confer susceptibility to congenital heart defects in affected individuals. We reviewed the cardiac characteristics in four patients with 2q13 deletion admitted to our hospitals, and in published patients. Two of our patients had congenital heart defects, consisting in partial anomalous pulmonary venous connection, ostium secundum atrial septal defect ostium secundum, and small muscular ventricular septal defect in one of them, and aortic valve insufficiency with partial fusion of two commissures (incomplete bicuspid aortic valve) and mitral valve insufficiency due to trivial mitral valve prolapse in the other. The anatomic types of CHD in del2q13 syndrome are highly variable and distributed widely, including laterality defects, complex atrioventricular septal defect, septal anomalies, and cardiomyopathies. Cardiac evaluation should be part of the clinical workup at diagnosis of 2q13 deletion.

Atrioventricular canal defect and genetic syndromes: The unifying role of sonic hedgehog

The atrioventricular canal defect (AVCD) is a congenital heart defect (CHD) frequently associated with extracardiac anomalies (75%). Previous observations from a personal series of patients with AVCD and "polydactyly syndromes" showed that the distinct morphology and combination of AVCD features in some of these syndromes is reminiscent of the cardiac phenotype found in heterotaxy, a malformation complex previously associated with functional cilia abnormalities and aberrant Hedgehog (Hh) signaling. Hh signaling coordinates multiple aspects of left-right lateralization and cardiovascular growth. Being active at the venous pole the secondary heart field (SHF) is essential for normal development of dorsal mesenchymal protrusion and AVCD formation and septation. Experimental data show that perturbations of different components of the Hh pathway can lead to developmental errors presenting with partially overlapping manifestations and AVCD as a common denominator. We review the potential role of Hh signaling in the pathogenesis of AVCD in different genetic disorders. AVCD can be viewed as part of a "developmental field," according to the concept that malformations can be due to defects in signal transduction cascades or pathways, as morphogenetic units which may be altered by Mendelian mutations, aneuploidies, and environmental causes.

Expanding the clinical and molecular spectrum of PRMT7 mutations: 3 additional patients and review

Protein arginine methyltransferase 7 (PRMT7) is a member of a family of enzymes that catalyze the transfer of methyl groups from S-adenosyl-l-methionine to nitrogen atoms on arginine residues. Arginine methylation is involved in multiple biological processes, such as signal transduction, mRNA splicing, transcriptional control, DNA repair, and protein translocation. Currently, 7 patients have been described harboring compound heterozygous or homozygous variants in the PRMT7 gene, causing a novel intellectual disability syndrome, known as SBIDDS syndrome (Short Stature, Brachydactyly, Intellectual Developmental Disability, and Seizures). We report on 3 additional patients from 2 consanguineous families with severe/moderate intellectual disability, short stature, brachydactyly and dysmorphisms. Exome sequencing revealed 2 novel homozygous mutations in PRMT7. Our findings expand the clinical and molecular spectrum of homozygous PRMT7 mutations, associated to the SBIDDS syndrome, showing a possible correlation between the type of mutation and the severity of the phenotype.

Biallelic mutations in DYNC2LI1 are a rare cause of Ellis-van Creveld syndrome

Ellis-van Creveld syndrome (EvC) is a chondral and ectodermal dysplasia caused by biallelic mutations in the EVC, EVC2 and WDR35 genes. A proportion of cases with clinical diagnosis of EvC, however, do not carry mutations in these genes. To identify the genetic cause of EvC in a cohort of mutation-negative patients, exome sequencing was undertaken in a family with 3 affected members, and mutation scanning of a panel of clinically and functionally relevant genes was performed in 24 additional subjects with features fitting/overlapping EvC. Compound heterozygosity for the c.2T>C (p.Met1?) and c.662C>T (p.Thr221Ile) variants in DYNC2LI1, which encodes a component of the intraflagellar transport-related dynein-2 complex previously found mutated in other short-rib thoracic dysplasias, was identified in the 3 affected members of the first family. Targeted resequencing detected compound heterozygosity for the same missense variant and a truncating change (p.Val141*) in 2 siblings with EvC from a second family, while a newborn with a more severe phenotype carried 2 DYNC2LI1 truncating variants. Our findings indicate that DYNC2LI1 mutations are associated with a wider clinical spectrum than previously appreciated, including EvC, with the severity of the phenotype likely depending on the extent of defective DYNC2LI1 function.

Visual perception skills: a comparison between patients with Noonan syndrome and 22q11.2 deletion syndrome

Ventral and dorsal streams are visual pathways deputed to transmit information from the photoreceptors of the retina to the lateral geniculate nucleus and then to the primary visual cortex (V1). Several studies investigated whether one pathway is more vulnerable than the other during development, and whether these streams develop at different rates. The results are still discordant. The aim of the present study was to understand the functionality of the dorsal and the ventral streams in two populations affected by different genetic disorders, Noonan syndrome (NS) and 22q11.2 deletion syndrome (22q11.2DS), and explore the possible genotype-phenotype relationships. 'Form coherence' abilities for the ventral stream and 'motion coherence' abilities for the dorsal stream were evaluated in 19 participants with NS and 20 participants with 22q11.2DS. Collected data were compared with 55 age-matched controls. Participants with NS and 22q11.2DS did not differ in the form coherence task, and their performance was significantly lower than that of controls. However, in the motion coherence task, the group with NS and controls did not differ, and both obtained significantly higher scores than the group with 22q11.2DS. Our findings indicate that deficits in the dorsal stream are related to the specific genotype, and that in our syndromic groups the ventral stream is more vulnerable than the dorsal stream.

Thricho-rhino-phalangeal syndrome and severe osteoporosis: a rare association or a feature? An effective therapeutic approach with biphosphonates

Trichorhinophalangeal syndrome (TRPS) is a rare, autosomal dominant malformation syndrome characterized by hair, craniofacial and skeletal abnormalities, skin laxity, deformation of phalanges and anomalies of pelvis, femurs, and tibias. Three subtypes have been described: TRPS I, caused by mutations in TRPS1 gene on chromosome 8; TRPS II, a microdeletion syndrome affecting the TRPS1 and EXT1 genes; and TRPS III, a form with severe brachydactyly, due to short metacarpals, and severe short stature, but without exostoses. We present the case of a 7-year-old boy, affected by TRPS with a severe osteoporosis and several spontaneous bone fractures, an association described only once in the literature, successfully treated with biphosphonates. Bone mineral density (BMD) at dual-energy X-ray Absorptiometry (DXA) was of 0.331 g/cm(2) at lumbar spine with. He had four spontaneous femoral fractures in a year, and for this reason he was been operated for positioning intramedullary osteosynthesis and orthopedic supports. Due to the severity of the clinical and radiological pattern it was established, after approval of the Ethical Committee, to begin off-label therapy with infusions of neridronate at a dose of 2 mg/kg IV every 3 months. The treatment was, in this patient, effective both in terms of clinical (absence of new fractures) and mineralomethric (+45% BMD ath the lumbar level). We therefore suggest that treatment with biphosponates can be taken in account as a possible therapeutic option in case of bone fragility in patients with TRPSI.

RASopathies: Clinical Diagnosis in the First Year of Life

Diagnosis within Noonan syndrome and related disorders (RASopathies) still presents a challenge during the first months of life, since most clinical features used to differentiate these conditions become manifest later in childhood. Here, we retrospectively reviewed the clinical records referred to the first year of life of 57 subjects with molecularly confirmed diagnosis of RASopathy, to define the early clinical features characterizing these disorders and improve our knowledge on natural history. Mildly or markedly expressed facial features were invariably present. Congenital heart defects were the clinical issue leading to medical attention in patients with Noonan syndrome and LEOPARD syndrome. Feeding difficulties and developmental motor delay represented the most recurrent features occurring in subjects with cardiofaciocutaneous syndrome and Costello syndrome. Thin hair was prevalent among SHOC2 and BRAF mutation-positive infants. Café-au-lait spots were found in patients with LS and PTPN11 mutations, while keratosis pilaris was more common in individuals with SOS1, SHOC2 and BRAF mutations. In conclusion, some characteristics can be used as hints for suspecting a RASopathy during the first months of life, and individual RASopathies may be suspected by analysis of specific clinical signs. In the first year of life, these include congenital heart defects, severity of feeding difficulties and delay of developmental milestones, hair and skin anomalies, which may help to distinguish different entities, for their subsequent molecular confirmation and appropriate clinical management.

Needs and challenges of daily life for people with Down syndrome residing in the city of Rome, Italy

BACKGROUND

Population-based surveys on the quality of life of people with Down syndrome (DS) are difficult to perform because of ethical and legal policies regarding privacy and confidential information, but they are essential for service planning. Little is known about the sample size and variability of quality of life of people with DS living in the city of Rome, which has a population of 2.7 million inhabitants. The aim of the present study is to explore the needs and challenges in health, social integration and daily life, of people with DS living in Rome.

METHODOLOGY

A cross-sectional, census-based survey was conducted in 2006. All family doctors (3016 in total) of the National Health Service were involved by the Statistical Bureau of the Municipality of Rome. As per the census, every resident citizen is registered with a family doctor and every person with disabilities is coded. Associations for Down Syndrome encouraged their members to participate in the research. Questionnaires were completed by families of people with DS, in accordance with privacy laws.

FINDINGS

An initial survey, conducted via a letter and a telephone contact with family doctors, identified 884 people with DS residing in the city of Rome. Data on the medical and social conditions of 518 people with DS, ranging in age from 0 to 64 years, were collected. Some 88% of these were living with their original family; 82.1% had one or more siblings, and 19.5% had lost one or both parents. A full 100% of children with DS were enrolled in the public school system. This ensures that they are fully occupied and entirely integrated in society. After secondary school there is a lack of opportunities. Thus, only 10% of adults were working with a regular contract. A mere 42.2% of people with DS aged 25-30 were involved in some form of regular activity (although not always on a daily basis). After the age of 30, the percentage of people demonstrating decline in function increased sharply, while disability-related support decreased. In other words, as people with DS age, daily life evolves increasingly around the home, with only occasional outdoor activities.

CONCLUSION

The health, employment and social needs of the majority of people with DS in the city of Rome are not being met. The findings of this study underscore the urgent need for more comprehensive inclusion in society of adults with DS and for the provision of support services to create an enabling environment for inclusion. Because of the variability of performance among individuals with DS, there is a need to create more case-specific options in terms of work, living arrangements, social networking and medical services. Schooling and social inclusion in childhood alone do not guarantee a satisfactory quality of life in adulthood. It is argued herewith that policy of inclusion and support should extend over the entire lifetime of people with DS.

Needs and challenges of daily life for people with Down syndrome residing in the city of Rome, Italy

BACKGROUND

Population-based surveys on the quality of life of people with Down syndrome (DS) are difficult to perform because of ethical and legal policies regarding privacy and confidential information, but they are essential for service planning. Little is known about the sample size and variability of quality of life of people with DS living in the city of Rome, which has a population of 2.7 million inhabitants. The aim of the present study is to explore the needs and challenges in health, social integration and daily life, of people with DS living in Rome.

METHODOLOGY

A cross-sectional, census-based survey was conducted in 2006. All family doctors (3016 in total) of the National Health Service were involved by the Statistical Bureau of the Municipality of Rome. As per the census, every resident citizen is registered with a family doctor and every person with disabilities is coded. Associations for Down Syndrome encouraged their members to participate in the research. Questionnaires were completed by families of people with DS, in accordance with privacy laws.

FINDINGS

An initial survey, conducted via a letter and a telephone contact with family doctors, identified 884 people with DS residing in the city of Rome. Data on the medical and social conditions of 518 people with DS, ranging in age from 0 to 64 years, were collected. Some 88% of these were living with their original family; 82.1% had one or more siblings, and 19.5% had lost one or both parents. A full 100% of children with DS were enrolled in the public school system. This ensures that they are fully occupied and entirely integrated in society. After secondary school there is a lack of opportunities. Thus, only 10% of adults were working with a regular contract. A mere 42.2% of people with DS aged 25-30 were involved in some form of regular activity (although not always on a daily basis). After the age of 30, the percentage of people demonstrating decline in function increased sharply, while disability-related support decreased. In other words, as people with DS age, daily life evolves increasingly around the home, with only occasional outdoor activities.

CONCLUSION

The health, employment and social needs of the majority of people with DS in the city of Rome are not being met. The findings of this study underscore the urgent need for more comprehensive inclusion in society of adults with DS and for the provision of support services to create an enabling environment for inclusion. Because of the variability of performance among individuals with DS, there is a need to create more case-specific options in terms of work, living arrangements, social networking and medical services. Schooling and social inclusion in childhood alone do not guarantee a satisfactory quality of life in adulthood. It is argued herewith that policy of inclusion and support should extend over the entire lifetime of people with DS.

New mutations in ZFPM2/FOG2 gene in tetralogy of Fallot and double outlet right ventricle

Conotruncal defects (CTDs) represent 15-20% of all congenital heart defects. Mutations in a number of genes have been associated with CTD in humans and animal models. We investigated the occurrence and the prevalence of GATA4, NKX2.5, ZFPM2/FOG2, GDF1, and ISLET1 gene mutations in a large cohort of individuals with CTD, including tetralogy of Fallot with or without pulmonary atresia (TOF, 178 patients), double outlet right ventricle (DORV, 13 patients), and truncus arteriosus (11 patients). Denaturing high-performance liquid chromatography (DHPLC) analysis followed by bidirectional sequencing disclosed no putative pathogenic mutation in GATA4, ISLET1, and GDF1 genes. Two novel (Ile227Val, Met544Ile) and one previously reported (Glu30Gly) possibly pathogenic missense variants were identified in the ZFPM2/FOG2 gene in 3 sporadic patients of 202 (1.5%) with CTD, including 1 of 178 (0.6%) with TOF and 2 of 13 (15.4%) with DORV. Mutation analysis also detected one known missense change (Arg25Cys) in NKX2.5 gene in two (1.1%) sporadic patients with TOF. These sequence alterations were found to be absent in 500 population-matched controls. In conclusion, the present results (i) indicate and confirm that mutations in the GATA4, GDF1, and ISLET1 genes are not major determinants in the pathogenesis of TOF, (ii) provide supportive evidence of an association between ZFPM2/FOG2 gene and TOF/DORV, and (iii) provide additional examples of the possible contribution of the Arg25Cys change in the NKX2.5 to a small number of TOF cases.

Mild ring 17 syndrome shares common phenotypic features irrespective of the chromosomal breakpoints location

Ring 17 syndrome is a rare disorder with clinical features influenced by the presence or deletion of the Miller-Dieker critical region (MDCR). Presence of the MDCR is associated with a mild phenotype, including growth delay (GD), mental retardation (MR), seizures, cafè au lait skin (CALS) spots and minor facial dysmorphisms. Previous studies have been mainly focused on this locus providing poor information about the role of other genes located on the p- and q-arms. Here, we used bacterial artificial chromosome (BAC)/P1 artificial chromosome (PAC) and fosmid clones as fluorescence in situ hybridization (FISH) probes to perform a cyto-molecular analysis of a ring 17 case and found that the breakpoints were close to the telomeric ends. METRNL is the sole gene located on the q-arm terminal end, whereas two open reading frames and the RPH3AL gene are located on the terminal p-arm. To detect possibly unrevealed small deletions involving the transcription units, we used subcloned FISH probes obtained by long-range polymerase chain reaction (PCR), which showed that the investigated regions were preserved. Comparing our findings with other reports, it emerges that different breakpoints, involving (or not) large genomic deletions, present overlapping clinical aspects. In conclusion, our data suggest that a mechanism based on gene expression control besides haploinsufficiency should be considered to explain the common phenotypic features found in the mild ring 17 syndrome.

Masked complex chromosome rearrangement in a child thought to have del(8qter) as the sole cytogenetic abnormality

Cytogenetic analyses of constitutional diseases have disclosed several chromosomal rearrangements. At the molecular level, these rearrangements often result in the breakage of genes or alteration of genome architecture. Fluorescence in situ hybridization (FISH) and molecular investigations of a patient showing hypotonia and dysmorphic traits revealed a masked complex chromosome abnormality previously detected by G-banding as a simple 8qter deletion. To characterize the genetic rearrangements panels of bacterial artificial chromosomes (BACs) covering 8q24.22-->qter were constructed, and short tandem repeats (STRs) were used to refine the localization of the breakpoints and to assess the parental origin of the defect. Chromosome 8 displayed the breakpoint at 8q24.22 and an unexpected distal breakpoint at 8q24.23 resulting in unbalanced translocation of a small 8q genomic region on the chromosome 16qter. The study of the 16qter region revealed that the 16q subtelomere was retained and the translocated material of distal 8q was juxtaposed. Moreover, molecular analyses showed that part of the translocated 8qter segment on der(16) was partially duplicated, inverted and that the rearrangement arose in the paternal meiosis. These findings emphasize the complexity of some only apparently simple chromosomal rearrangements and suggest a subtelomeric FISH approach to enhance diagnostic care when a cytogenetic terminal deletion is found.

Congenital diaphragmatic hernia in CHARGE syndrome

Congenital diaphragmatic hernia (CDH) has been rarely described in CHARGE syndrome. We report a patient affected by CHARGE syndrome presenting with a right-sided Bochdalek-type diaphragmatic hernia, and collect the pertinent literature. Furthermore, we review the embryogenesis of the diaphragm and the pathogenesis of CDH to highlight if this malformation could be explained by a developmental anomaly of CHARGE. On the basis of our study, we suggest that patients affected by CDH, facial asymmetry and cardiovascular or urogenital malformations, should be actively screened for CHARGE syndrome findings.

Systemin regulates both systemic and volatile signaling in tomato plants

The prevailing reaction of plants to pest attack is the activation of various defense mechanisms. In tomato, several studies indicate that an 18 amino acid (aa) peptide, called systemin, is a primary signal for the systemic induction of direct resistance against plant-chewing pests, and that the transgenic expression of the prosystemin gene (encoding the 200 aa systemin precursor) activates genes involved in the plant response to herbivores. By using a combination of behavioral, chemical, and gene expression analyses, we report that systemin enhances the production of bioactive volatile compounds, increases plant attractivity towards parasitiod wasps, and activates genes involved in volatile production. Our data imply that systemin is involved in the systemic activation of indirect defense in tomato, and we conclude that a single gene controls the systemic activation of coordinated and associated responses against pests.

Pure trisomy 19p syndrome in an infant with an extra ring chromosome

We report a 12-month-old infant evaluated for severe hypotonia, psychomotor retardation, and facial dysmorphisms, including round face, high prominent forehead, downward slanted palpebral fissures, hypertelorism, short nose, chubby cheeks, long philtrum, anteverted lower lip, low-set asymmetric and dysmorphic ears. Karyotype analysis disclosed an extra mosaic ring chromosome, which included the whole 19p arm. Four additional patients with supernumerary ring 19 chromosomes have been reported, but none of them had pure trisomy 19p.

Two high throughput technologies to detect segmental aneuploidies identify new Williams-Beuren syndrome patients with atypical deletions

OBJECTIVE

To develop and compare two new technologies for diagnosing a contiguous gene syndrome, the Williams-Beuren syndrome (WBS).

METHODS

The first proposed method, named paralogous sequence quantification (PSQ), is based on the use of paralogous sequences located on different chromosomes and quantification of specific mismatches present at these loci using pyrosequencing technology. The second exploits quantitative real time polymerase chain reaction (QPCR) to assess the relative quantity of an analysed locus.

RESULTS

A correct and unambiguous diagnosis was obtained for 100% of the analysed samples with either technique (n = 165 and n = 155, respectively). These methods allowed the identification of two patients with atypical deletions in a cohort of 182 WBS patients. Both patients presented with mild facial anomalies, mild mental retardation with impaired visuospatial cognition, supravalvar aortic stenosis, and normal growth indices. These observations are consistent with the involvement of GTF2IRD1 or GTF2I in some of the WBS facial features.

CONCLUSIONS

Both PSQ and QPCR are robust, easy to interpret, and simple to set up. They represent a competitive alternative for the diagnosis of segmental aneuploidies in clinical laboratories. They have advantages over fluorescence in situ hybridisation or microsatellites/SNP genotyping for detecting short segmental aneuploidies as the former is costly and labour intensive while the latter depends on the informativeness of the polymorphisms.

Clinical manifestations of Deletion 22q11.2 syndrome (DiGeorge/Velo-Cardio-Facial syndrome)

Deletion 22q11.2 syndrome (Del22) (DiGeorge/Velo-Cardio-Facial syndrome) is characterized by congenital heart defect (CHD), palatal anomalies, facial dysmorphisms, neonatal hypocalcemia, immune deficit, speech and learning disabilities. CHD is present in 75% of patients with Del22. The most frequently seen cardiac malformations are "conotruncal" defects, including tetralogy of Fallot (TF), pulmonary atresia with ventricular septal defect (PA-VSD), truncus arteriosus (TA), interrupted aortic arch (IAA), and ventricular septal defect (VSD). The study of the specific "cardiac phenotype" in patients with Del22 shows that a particular cardiac anatomy can be identied in these subjects. In addition to CHD, various organ systems can be involved, so that a multidisciplinary approach is needed in the evaluation of patients with Del22.

High frequency of subtelomeric rearrangements in a cohort of 92 patients with severe mental retardation and dysmorphism

About 5-10% of patients with dysmorphisms, severe mental retardation, and normal standard karyotype are affected by subtelomeric chromosome rearrangements. Sequence homology between different chromosomes and variability between homologs make these regions more susceptible to breakage and reunion. We analyzed the telomeric regions of 92 of these patients, selected with strict clinical criteria. Fifteen individuals (16.3%) had subtelomeric rearrangements. Nine had a unique anomaly, which in one case had been inherited from a balanced parent. Six subjects had double segmental imbalances, including three de novo imbalances. This study provides further evidence for the plasticity of subtelomeric regions, which often results in cryptic rearrangements, and recommends stringent criteria for selecting patient candidates to telomere analysis.

Absorption of sugars and amino acids by the epidermis of Aphidius ervi larvae

Aphidius ervi Haliday (Hymenoptera, Braconidae) is an endophagous parasitoid of several aphid species of economic importance, widely used in biological control. The definition of a suitable artificial diet for in vitro mass production of this parasitoid is still an unresolved issue that, to be properly addressed, requires a deeper understanding both of its nutritional needs and of the functional properties of the larval epithelia involved in nutrient absorption. The experimental evidence presented in this paper unequivocally demonstrates that the uptake of sugars and amino acids takes place through the body surface of the larval stages of A. ervi. These nutrients are efficiently absorbed by the larval epidermis, but the transport rate progressively declines over time. The epidermis exhibits a cross-reactivity to antibodies raised against the mammalian facilitative glucose transporter GLUT2 and the sodium cotransporter SGLT1. The analysis of sugar transport sensitivity to specific inhibitors indicates the involvement of GLUT2-like transporters, while a role for SGLT1-like transporters is not supported. The peculiar pathways of nutrient absorption in A. ervi larvae further corroborate the general idea that the pre-imaginal stages of endophagous koinobiont Hymenoptera, like Metazoan parasites, show a high degree of physiological integration with their hosts.

Biased T-cell receptor repertoires in patients with chromosome 22q11.2 deletion syndrome (DiGeorge syndrome/velocardiofacial syndrome)

Chromosome 22q11.2 deletion (del22q11.2) syndrome (DiGeorge syndrome/velocardiofacial syndrome) is a common syndrome typically consisting of congenital heart disease, hypoparathyroidism, developmental delay and immunodeficiency. Although a broad range of immunologic defects have been described in these patients, limited information is currently available on the diversity of the T-cell receptor (TCR) variable beta (BV) chain repertoire. The TCRBV repertoires of nine patients with del22q11.2 syndrome were determined by flow cytometry, fragment size analysis of the third complementarity determining region (CDR3 spectratyping) and sequencing of V(D)J regions. The rate of thymic output and the phenotype and function of peripheral T cells were also studied. Expanded TCRBV families were detected by flow cytometry in both CD4+ and CD8+ T cells. A decreased diversity of TCR repertoires was also demonstrated by CDR3 spectratyping, showing altered CDR3 profiles in the majority of TCRBV families investigated. The oligoclonal nature of abnormal peaks detected by CDR3 spectratyping was confirmed by the sequence analysis of the V(D)J regions. Thymic output, evaluated by measuring TCR rearrangement excision circles (TRECs), was significantly decreased in comparison with age-matched controls. Finally, a significant up-regulation in the percentage, but not in the absolute count, of activated CD4+ T cells (CD95+, CCR5+, HLA-DR+), IFN-gamma - and IL-2-expressing T cells was detected. These findings suggest that the diversity of CD4 and CD8 TCRBV repertoires is decreased in patients with del22q11.2 syndrome, possibly as a result of either impaired thymic function and/or increased T-cell activation.

Spectrum of clinical variability in familial deletion 22q11.2: from full manifestation to extremely mild clinical anomalies

The 22q11.2 deletion (del22q11.2) syndrome is a genetic condition with wide interfamilial and intrafamilial variability in clinical expression. The aim of the present study was to review the prevalence of parental transmission in our series of patients with del22q11.2, and to analyse clinical findings of the affected parents. Parental transmission of del22q11.2 in our series was 17.2% (15/87), with a preferential maternal transmission (10/15). One or more major features of del22q11.2 were found in all deleted parents, but one of the mothers showed extremely mild clinical anomalies. The present data demonstrate that it should be current policy to test both parents of patients with del22q11.2, irrespective of the parental phenotype, in view of the fact that extremely mild clinical features can be detected in parents of deleted patients. This would provide accurate genetic counselling to del22q11.2 families, as relatively asymptomatic parents must be advised of the 50% risk of transmitting the deletion in a subsequent pregnancy. Various genetic and non-genetic factors, including modifier genes at separate loci, mosaicism, unstable mutations, allelic variations at the haploid locus, chance and environmental interaction, can be hypothesized to be involved in variable clinical expression, even in the same family.

Two novel mutations of the human Δ7-sterol reductase (DHCR7) gene in children with Smith–Lemli–Opitz syndrome

We analyzed seven unrelated children with the Smith-Lemli-Opitz syndrome (SLOS) for mutations in the delta7-sterol reductase gene by using SSCP and direct sequencing. We identified two novel mutations (V330M and R363C) in the DHCR7 gene. Reported mutations found in this study were T93M (3/14 alleles), E448K (2/14), and W151X, G244R, P329L, and R446Q (each found in one allele). The so-called common IVS8-1 G --> C was found in three alleles, confirming its relative rarity among Italian SLOS families. By using a scoring system, clinical severity did not seem to correlate with 7DHC levels and type of mutation. Expanding the spectrum of mutations in SLOS, our study does not support direct genotype-phenotype correlation.

Identification of a novel NOG gene mutation (P35S) in an Italian family with symphalangism

Symphalangism (SYM or SYM1) is an autosomal dominant disorder characterized by multiple joint fusions. The disease is caused by mutations of the NOG gene, that maps to chromosome 17q22. So far, only six independent NOG mutations have been identified. We have analysed an Italian family in which father and son had bilateral symphalangism and detected a novel NOG mutation (P35S), originated in the father from a c.914C>T transition. A different mutation in the same codon (P35R) has been previously described. Comparison between different noggin gene hortologs shows that codon 35 is conserved. Therefore, this codon should play an important role in NOG gene function. This is the first mutation described for NOG after the initial report of NOG mutations being causative of SYM.

Complete transposition of the great arteries: patterns of congenital heart disease in familial precurrence

BACKGROUND

Transposition of the great arteries (TGA) is considered to be associated only rarely with genetic syndromes and to have a low risk of precurrence among relatives of affected patients. Because most family studies have involved a relatively small number of patients and evaluated all types of TGA as a single group, we performed a large, prospective study investigating the precurrence of congenital heart disease in families of children with complete, nonsyndromic TGA.

METHODS AND RESULTS

From January 1997 through December 2000, 370 patients with nonsyndromic, complete TGA were consecutively evaluated and enrolled in the study. The occurrence of cardiac and noncardiac anomalies among relatives of the probands was investigated. Relatives with congenital heart disease were found in 37 of 370 families (10%), including 5 of 37 families (13.5%) with more than one affected relative. TGA itself was the most common precurrent malformation: complete TGA occurred in 6 families and congenitally corrected TGA occurred in 5 families. Precurrence risks for congenital heart disease were calculated at 1.8% (8 of 436) for siblings, 0.5% (4 of 740) for parents, 0.5% (16 of 3261) for first cousins, 0.2% (4 of 2101) for uncles/aunts, and 0.06% (1 of 1480) for grandparents.

CONCLUSIONS

The present study shows that TGA is not always sporadic in families. Precurrence of concordant cardiac defects within affected family members supports monogenic or oligogenic inheritance of TGA in certain kindreds. Moreover, the occurrence of complete TGA and congenitally corrected TGA among first-degree relatives in several different families strongly suggests an underlying pathogenetic link between these 2 malformations that has been previously unrecognized.

Ext-mutation analysis in Italian sporadic and hereditary osteochondromas

Osteochondromas represent the largest group of benign tumors of bone. Multiple osteochondromatosis or hereditary multiple exostoses (EXT) is an autosomal dominant inherited disorder characterized by the presence of multiple benign cartilage-capped exostoses. EXT is genetically heterogeneous with at least 3 chromosomal loci: EXT1 (8q24.1), EXT2 (11p11-p13), and EXT3 (19p). In <5% of EXT patients, the inactivation of both copies of EXT alleles (LOH) is associated with malignant transformation. We have analyzed the EXT1 and EXT2 genes in 9 unrelated EXT families and in a patient with a sporadic osteochondroma, all originating from Italy. Four families show an EXT1 mutation, consisting of a small deletion in 3 of them and a small insertion in the 4th. All these mutations lead to premature termination of translation and thus a truncated EXT1 protein. Three families presented EXT2 mutations consisting of nucleotide substitutions leading to alterations of the third intron splice-site, to an amino acid substitution and to a nonsense mutation. All these mutations cosegregate with the disease phenotype. The sporadic osteochondroma patient carried a novel missense mutation in exon 11 of EXT2 gene, leading to an amino acid substitution. Seven of these mutations have never been described before. EXT2 missense mutations were also confirmed by amino acids conservation between human and mouse and by analysis of a healthy control population. In conclusion, our study provide further evidence that loss of function of the EXT1 or EXT2 gene is the main cause of EXT supporting the putative tumor-suppressor function of these genes.

Exercise testing and 24-hour ambulatory blood pressure monitoring in children with Williams syndrome

The aim of the study was to assess workload capacity and blood pressure (BP) response to treadmill exercise and 24-hour BP monitoring in children with Williams syndrome. Seventeen children were examined (8 males and 9 females) whose mean age was 13.8 +/- 3.6 years. Six patients were on antihypertensive therapy. Each patient underwent clinical examination and measurement of BP at rest, during exercise, and during 24-hour monitoring. Two-dimensional echocardiogram and echo-Doppler of renal arteries were performed. The test was stopped for muscular fatigue or reduced cooperation. The patients, when compared to a population of healthy children, had reduced total time of exercise (7.3 +/- 1.9 vs 14.3 +/- 2.6 min, p < 0.001) and, at the same workload, increased heart rate (167 +/- 19 vs 145 +/- 16 beats/min, p < 0.001) and increased maximum systolic BP (146 +/- 27 vs 128 +/- 12 mmHg, p = 0.01). Ambulatory blood pressure measurement values showed higher systolic blood pressure both during daytime and nighttime. Our study confirms that children and adolescents with Williams syndrome are at high risk for hypertension, probably related to the alterations of large arteries. The data relating to the synthesis of elastin may have a direct relationship to the compliance of the arterial system, leading to hypertension.

Coeliac disease in Williams syndrome

BACKGROUND

Coeliac disease (CD) has been reported in several patients affected by chromosomal disorders, including Down syndrome (DS) and Turner syndrome (TS). CD has also been found in sporadic Williams syndrome (WS) patients. In this study, CD was evaluated in a consecutive series of patients with WS, in order to estimate if the prevalence of CD in WS patients is higher than in the general population.

METHODS AND RESULTS

A consecutive series of 63 Italian patients with WS was studied by analysing the dosage of antigliadin antibodies (AGA) IgA and antiendomisium antibodies (AEA). In patients with positive AGA and AEA, small bowel biopsy was performed. The prevalence of CD in our WS population was compared with that estimated in a published series of 17 201 Italian students. Seven WS patients were found to be positive for AGA IgA and AEA. Six of them underwent small bowel biopsy, which invariably disclosed villous atrophy consistent with CD. The prevalence of CD in the present series of WS patients was 9.5% (6/63), compared to 0.54% (1/184) in the Italian students (p<0.001).

CONCLUSION

The present results suggest that the prevalence of CD in WS is higher than in the general population and is comparable to that reported in DS and TS. AGA and AEA screening is recommended in patients with WS.

Larval anatomy and structure of absorbing epithelia in the aphid parasitoid Aphidius ervi Haliday (Hymenoptera, Braconidae)

The present work describes Aphidius ervi Haliday (Hymenoptera, Braconidae) larval anatomy and development, focusing on time-related changes of body structure and cell ultrastructure, especially of the epithelial layers involved in nutrient absorption. Newly hatched 1st instar larvae of A. ervi are characterised by gut absence and a compact cluster of cells makes up their body. As the parasitoid larva develops, the central undifferentiated cell mass becomes hollowed out, leading to the formation of gut anlage. This suggests that absorption of nutrients at that stage may take place through the body surface, as more directly demonstrated by the occurrence on the epidermis of proteins associated with transepithelial transport, such as Na(+)/K(+)-ATPase and alkaline phosphatase (ALP). Second instar larvae show the presence of the gut with a well-differentiated brush border and a peritrophic membrane. Gut cells are filled by masses of glycogen granules and lipid droplets. The tracheal system starts to be visible. The haemocoel becomes evident in late 2nd instar, and contains large silk glands. Mature 3rd instar larvae are typically hymenopteriform. The midgut accounts for most of the body volume and is actively involved in nutrient absorption, as indicated by the well developed brush border and by the presence of Na(+)/K(+)-ATPase and ALP on the basolateral and luminal membrane respectively. At this stage, large lipid droplets have gradually replaced the cellular glycogen stores in the midgut cells. The tracheae are completely differentiated, but their internal lumen still contains fibrillar material, suggesting that they are not functional as long as host fluids bath the parasitoid larva. In late 3rd instar larvae, silk glands, structurally similar to Malpighian tubules, show a very intense vesicular traffic toward the internal lumen, which, eventually, results in being filled by secretion products, suggesting the possible recycling of metabolic waste products during mummy formation.

Congenital heart defects in Kabuki syndrome

Kabuki makeup (Niikawa-Kuroki) syndrome (KS) is characterized by distinct facial anomalies, mental retardation, congenital heart defect (CHD), and skeletal malformations. In the present study we analyze cardiac characteristics and differences in sex prevalence of specific CHDs in our series of patients with KS and review published reports from the literature. Between January 1992 and February 2000, 60 patients (37 males and 23 females) with KS underwent phenotypic and cardiac evaluations at our hospital. CHD was diagnosed in 35 (58%) of our patients. Aortic coarctation (COA) (23%), atrial septal defect (ASD) (20%), and ventricular septal defect (VSD) (17%) were the most frequent CHDs in our series and in previous reports from the literature. Male preponderance was noted in patients with COA. In conclusion, CHD is a cardinal feature of KS. There is an overlap between cardiac malformations of KS and those of Turner syndrome. Male preponderance in patients with KS and COA supports the hypothesis that genes located on the X chromosome may be involved in determining KS in some patients. The high prevalence of CHD prompts accurate re-examination of patients evaluated by pediatric cardiologists in order to identify mild and still unrecognized cases of KS.

Pulmonary atresia with ventricular septal defect: prevalence of deletion 22q11 in the different anatomic patterns

BACKGROUND

Pulmonary atresia with ventricular septal defect (PA-VSD) is one of the most common cardiac defects associated with DiGeorge syndrome. The pattern of the pulmonary circulation determines the complexity of this type of heart disease. The aim of this study was to establish the prevalence of DiGeorge syndrome with deletion 22q11 in patients with simple and complex PA-VSD.

METHODS

Since 1993 we have studied 128 consecutive patients affected by PA-VSD. In 90 of our patients the PA-VSD was considered "simple" (group I), because it was not associated with any other cardiac defects. In the other 38 children the PA-VSD was considered "complex" (group II) owing to the presence of heterotaxia, tricuspid atresia, a double-inlet left ventricle, transposition of the great arteries and congenitally corrected transposition of the great arteries.

RESULTS

In group I, 38 patients (42%) had genetic syndromes or major extracardiac anomalies; deletion 22q11 was detected in 31% of cases. Major aortopulmonary collateral arteries were present in 50% of group I patients and in 57% of those with deletion 22q11. In group II, 10 patients (26%) had genetic syndromes or major extracardiac anomalies but none had deletion 22q11 (p < 0.005); in no case was the presence of major aortopulmonary collateral arteries observed (p < 0.005).

CONCLUSIONS

PA-VSD is an anatomically and morphogenetically heterogeneous disease: in the setting of DiGeorge syndrome or velocardiofacial syndrome, PA-VSD is associated with a peculiar cardiac pattern and is due to deletion 22, whereas in case of nonsyndromic PA-VSD or when this disease is associated with different syndromes or with other types of cardiac defects, it is due to other morphogenetic mechanisms.

Auxological evaluation in patients with DiGeorge/velocardiofacial syndrome (deletion 22q11.2 syndrome)

PURPOSE

Patients with microdeletion of chromosome 22q11.2 (del22q11) were studied, in order to evaluate auxological parameters and to correlate growth patterns with the presence of main clinical characteristics of the syndrome.

METHODS

Between January 1995 and March 2000, auxological parameters (weight, height, head circumference, and bone age) of 73 patients with del22q11 were collected. Five subgroups of patients were distinguished: Group I (37 patients) included patients aged between 0.3 and 4 years, Group II (20 patients) included patients aged between 5 and 10 years, Group III (16 patients) included patients aged between 11 and 16.3 years. The presence or absence of some clinical features was correlated to growth patterns.

RESULTS

Weight: in Group I, 5 of 37 (13.5%) patients were below the 3rd percentile, 29 of 37 (78.3%) were below the mean percentile, none was overweight; in Group II, 13 of 20 (65%) patients were between the 10th and the 50th percentiles; in Group III, weight corresponded to the 97th percentile in 5 of 16 (31.2%) patients, and in 2/16 (12.5%) adolescents, the weight measurements were even above the 97th percentile. Height: short stature was detected in 7 of 73 (9.6%) of the total patients; the patients with short stature were all < 10 years old; the height was within the normal age in all adolescent patients. Head circumference: it was below the 3rd percentile in 7 of 73 (9.6%), between the 3rd and the 25th percentiles in 36 of 73 (49.3%) patients, between the 25th and the 75th percentiles in 20 of 73 (27.3%) patients, and between the 75th and the 97th percentiles in 10 of 73 (13.7%) patients. Bone age: mean +/- SD bone age was -0.25 +/- 0.78 years. Comparisons: the only statistically significant correlation was that between the presence of feeding difficulties and underweight.

CONCLUSION

Auxological parameters of children with del22q11 are characterized by: (1) weight deficiency in the first years of age, (2) weight normalization in the following years, (3) development of obesity in adolescence, (4) short stature in 10% of the patients, (5) normal height in adolescents, (6) slight delay in bone age in infancy, (7) microcephaly in 10% of the patients.

Clinical manifestations of Noonan syndrome

Noonan syndrome is a common genetic disorder characterized by facial anomalies, congenital heart defect, short stature, webbed neck, chest deformities and undescended testes. The phenotypic expression of Noonan syndrome is extremely variable, with some affected subjects showing only minor features of the syndrome. Cardiac malformations are also heterogeneous. Pulmonary stenosis, with or without dysplastic pulmonary valve and hypertrophic cardiomyopathy, are the "classic" cardiac defects reported in Noonan syndrome. However, atrial septal defect, atrioventricular septal defect, left-sided obstructive lesions, tetralogy of Fallot and patent ductus arteriosus have also been described. Autosomal dominant inheritance has been documented in some families, although many cases appear to be sporadic. The diagnosis of Noonan syndrome is at present purely clinical, because a "diagnostic" test is not available. Indeed, although a gene for Noonan syndrome has been recently mapped by linkage analysis to chromosome 12q, the gene or genes of the syndrome have not been yet cloned.

Anatomic patterns of conotruncal defects associated with deletion 22q11

PURPOSE

Patients with cardiovascular malformations (CVMs) and deletion 22q11 from our series were studied in order to (1) analyze the association with dysmorphic features and noncardiac anomalies, (2) identify specific cardiac patterns and the distinctive association with additional CVMs.

METHODS

From 1993 to 2000, 931 patients with CVM (95 with a clinical diagnosis of DiGeorge/velocardiofacial syndrome (DG/VCFS), 208 with different genetic syndromes, 628 without dysmorphic features) underwent accurate cardiac assessment, clinical and phenotypical examination, and screening for deletion 22q11 by fluorescence in situ hybridization (FISH).

RESULTS

Deletion 22q11 was detected in 88 of the total patients, and in 87 of the 95 patients with a clinical diagnosis of DG/VCFS. Only one patient among the 628 without dysmorphic features had deletion 22q11. Conotruncal heart defects were the most common CVMs, often presenting in association with additional anomalies in four areas of the cardiovascular system: (1) the aortic arch can be right sided, cervical, double, and the subclavian artery can be aberrant, (2) the pulmonary arteries can present discontinuity, diffuse hypoplasia, discrete stenosis, defect of arborization and major aortopulmonary collateral arteries (MAPCA), (3) the infundibular septum can be malaligned, hypoplastic, or absent, (4) the semilunar valves can be bicuspid, severely dysplastic, insufficient, or stenotic.

CONCLUSION

In subjects with deletion 22q11 CVM is virtually always associated with one or more noncardiac anomalies. Deletion 22q11 is exceptionally rare in children with nonsyndromic CVMs. Specific patterns of CVMs are observed in patients with deletion 22q11, including (1) anomalies of the aortic arch, (2) anomalies of the pulmonary arteries and of the pulmonary blood supply, (3) defects of the infundibular septum, (4) malformations of the semilunar valves. These additional CVMs may influence the surgical treatment of these patients.

Congenital heart disease and genetic syndromes: specific correlation between cardiac phenotype and genotype

The increasing role of genetic factors in the etiology of congenital heart defects is shown by the high frequency of genetic syndromes and extracardiac malformations in these patients. The accurate study of cardiac anatomy disclosed that peculiar morphologic subtypes of heart defects are related to specific genetic conditions. The correlation between anatomic cardiac patterns and some genetic anomalies (trisomy, deletion, mutation) suggests that specific morphogenetic mechanisms put in motion by gene(s) can result in a specific cardiac phenotype. In this review we analyze the cardiac morphology and the frequent genetic syndromes in five groups of congenital heart diseases: right-sided obstructions, left-sided obstructions, atrioventricular canal defects, ventricular septal defects, and conotruncal defects. Progress in this field is due not only to new research in molecular biology, but also to the attention of clinicians to a detailed cardiac diagnosis and to specific correlations between genotype and phenotype.

Heterotaxy with left atrial isomerism in a patient with deletion 18p

We report on a female infant with partial deletion of the short arm of chromosome 18 (del 18p) and heterotaxy with left atrial isomerism. Congenital heart defect (CHD) is found in 10% of the literature reports. Interestingly, situs abnormalities have been diagnosed in four patients with del 18p, including ours. This finding could imply that a locus or loci involved in the development of normal body situs lies within this chromosomal region. Del 18p must be consid- ered when evaluating a patient with phenotypic anomalies and CHD in lateralization defects.

Heterotaxy with left atrial isomerism in a patient with deletion 18p

We report on a female infant with partial deletion of the short arm of chromosome 18 (del 18p) and heterotaxy with left atrial isomerism. Congenital heart defect (CHD) is found in 10% of the literature reports. Interestingly, situs abnormalities have been diagnosed in four patients with del 18p, including ours. This finding could imply that a locus or loci involved in the development of normal body situs lies within this chromosomal region. Del 18p must be consid- ered when evaluating a patient with phenotypic anomalies and CHD in lateralization defects.

Deletion of a 5-cM region at chromosome 8p23 is associated with a spectrum of congenital heart defects

BACKGROUND

Cytogenetic evidence suggests that the haploinsufficiency of > or =1 gene located in 8p23 behaves as a dominant mutation, impairing heart differentiation and leading to a wide spectrum of congenital heart defects (CHDs), including conotruncal lesions, atrial septal defects, atrioventricular canal defects, and pulmonary valve stenosis. An 8p heart-defect-critical region was delineated, and the zinc finger transcription factor GATA4 was considered a likely candidate for these defects. We narrowed this region and excluded a major role of GATA4 in these CHDs.

METHODS AND RESULTS

We studied 12 patients (7 had CHD and 5 did not) with distal 8p deletions from 9 families by defining their chromosome rearrangements at the molecular level by fluorescent in situ hybridization and short-tandem repeat analysis. Subjects with 8p deletions distal to D8S1706, at approximately 10 cM from the 8p telomere, did not have CHD, whereas subjects with a deletion that included the more proximal region suffered from the spectrum of heart defects reported in patients with 8p distal deletions. The 5-cM critical region is flanked distally by D8S1706 and WI-8327, both at approximately 10 cM, and proximally by D8S1825, at 15 cM. Neither GATA4 nor angiopoietin-2 (ANGPT2; a gene in 8p23 involved in blood vessel formation) were found to be deleted in some of the critical patients. We also found that CHDs are not related to the parental origin of deletion.

CONCLUSIONS

Haploinsufficiency for a gene between WI-8327 and D8S1825 is critical for heart development. A causal relationship does not seem to exist between GATA4 and ANGPT2 haploinsufficiency and CHDs.