New Insights into Kleefstra Syndrome: Report of Two Novel Cases with Previously Unreported Features and Literature Review.

Kleefstra syndrome (KS) is a rare genetic condition resulting from either 9q34.3 microdeletions or mutations in the EHMT1 gene located in the same genomic region. To date, approximately 100 patients have been reported, thereby allowing the core phenotype of KS to be defined as developmental delay/intellectual disability, generalized hypotonia, neuropsychiatric anomalies, and a distinctive facial appearance. Here, to further expand the knowledge on genotype and phenotype of this condition, we report 2 novel cases: one patient carrying a 46-kb 9q34.3 deletion and showing macrocephaly never described in KS, and a second patient carrying a classic 9q34.3 deletion, presenting with a previously unreported skeletal feature (postaxial polydactyly of the right foot) and an unusual brain anomaly (olfactory bulb hypoplasia) observed via magnetic resonance imaging. Further, we provide a review of the current literature regarding KS and compare these 2 patients with those previously described, thereby confirming that the genotype-phenotype correlation in KS remains difficult to determine.

Novel TMEM67 mutations and genotype-phenotype correlates in meckelin-related ciliopathies.

Human ciliopathies are hereditary conditions caused by defects of proteins expressed at the primary cilium. Among ciliopathies, Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS) and nephronophthisis (NPH) present clinical and genetic overlap, being allelic at several loci. One of the most interesting gene is TMEM67, encoding the transmembrane protein meckelin. We performed mutation analysis of TMEM67 in 341 probands, including 265 JSRD representative of all clinical subgroups and 76 MKS fetuses. We identified 33 distinct mutations, of which 20 were novel, in 8/10 (80%) JS with liver involvement (COACH phenotype) and 12/76 (16%) MKS fetuses. No mutations were found in other JSRD subtypes, confirming the strong association between TMEM67 mutations and liver involvement. Literature review of all published TMEM67 mutated cases was performed to delineate genotype-phenotype correlates. In particular, comparison of the types of mutations and their distribution along the gene in lethal versus non lethal phenotypes showed in MKS patients a significant enrichment of missense mutations falling in TMEM67 exons 8 to 15, especially when in combination with a truncating mutation. These exons encode for a region of unknown function in the extracellular domain of meckelin.

SHOX duplications found in some cases with type I Mayer-Rokitansky-Kuster-Hauser syndrome.

PURPOSE: The Mayer-Rokitansky-Küster-Hauser syndrome is defined as congenital aplasia of müllerian ducts derived structures in females with a normal female chromosomal and gonadal sex. Most cases with Mayer-Rokitansky-Küster-Hauser syndrome are sporadic, although familial cases have been reported. The genetic basis of Mayer-Rokitansky-Küster-Hauser syndrome is largely unknown and seems heterogeneous, and a small number of cases were found to have mutations in the WNT4 gene. The aim of this study was to identify possible recurrent submicroscopic imbalances in a cohort of familial and sporadic cases with Mayer-Rokitansky-Küster-Hauser syndrome. METHODS: Multiplex ligation-dependent probe amplification was used to screen the subtelomeric sequences of all chromosomes in 30 patients with Mayer-Rokitansky-Küster-Hauser syndrome (sporadic, n = 27 and familial, n = 3). Segregation analysis and pyrosequencing were applied to validate the MLPA results in the informative family. RESULTS: Partial duplication of the Xpter pseudoautosomal region 1 containing the short stature homeobox (SHOX) gene was detected in five patients with Mayer-Rokitansky-Küster-Hauser syndrome (familial, n = 3 and sporadic, n = 2) and not in 53 healthy controls. The duplications were not overlapping, and SHOX was never entirely duplicated. Haplotyping in the informative family revealed that SHOX gene duplication was inherited from the unaffected father and was absent in two healthy sisters. CONCLUSIONS: Partial duplication of SHOX gene is found in some cases with both familial and sporadic Mayer-Rokitansky-Küster-Hauser type I syndrome.

Triple X syndrome: characteristics of 42 Italian girls and parental emotional response to prenatal diagnosis.

We report clinical and behavioural evaluation data in 42 Italian girls with triple X syndrome whose diagnosis was made prenatally between 1998 and 2006 in three Italian centres. At initial evaluation, reproductive and medical histories were collected. Clinical assessment of the child was performed by a clinical geneticist and included a detailed personal history, physical evaluation and auxological measurements. To analyse how parents coped with specific events in the prenatal and postnatal periods, we conducted an interview that included 35 specific questions designed to elicit retrospective judgements on prenatal communication, present and future worries, needs and expectations. In a subset of probands, we also administered the formal Italian Temperament Questionnaire assessment test that investigates adaptation, general environment and socialisation. This test also assesses the emotional component of temperament. Clinical results in the affected children are similar to those previously reported with evidence of increased growth in the pre-puberal age and an average incidence of congenital malformation and health needs. Median age for the time first words were pronounced was 12 months, showing a slight delay in language skills, which tended to improve by the time they reached school age. Parental responses to the interview demonstrated residual anxiety but with a satisfactory adaptation to and a positive recall of the prenatal counselling session. Parental adaptation of the 47,XXX girls require indeed a proper educational support. This support seems to be available in Italy. An integrated approach to prenatal counselling is the best way to manage the anxiety and falsely imagined consequences that parents feel after being told that their foetus bears such a genetic abnormality.

Discordant prenatal phenotype and karyotype of monozygotic twins characterized by the unequal distribution of two cell lines investigated by different methods: a review.

We present the case of a monozygotic twin pregnancy discordant for phenotype and karyotype. A chorionic villus sample was performed at the 11th week of gestation in a primigravida because of cystic hygroma detected by ultrasound in one twin of a monochorionic, biamniotic pregnancy. Rapid testing by means of quantitative fluorescence polymerase chain reaction and conventional karyotyping, obtained by both short- and long-term culture, revealed a homogeneous monosomy X (45,X). Amniocentesis was performed separately for both twins before termination and showed an homogeneous monosomy X in one sample and a 46,X,del(X)(p11.1) karyotype in the other one. Postmortem fetal tissues culture confirmed the discordant karyotype between the two embryos. Placental samples obtained after termination revealed the cell line which was not detected at chorionic villus sampling. Based on this and previous reports, we suggest that in cases of a phenotypic discordance detected at ultrasound in the first trimester, it is advisable to perform a karyotype analysis on amniocytes because it better reflects fetal constitution rather than chorionic villi or lymphocytes in case of heterokaryotipic monosomy X monochorionic twins.

Chromosome 17q21.31 duplication syndrome: Description of a new familiar case and further delineation of the clinical spectrum.

INTRODUCTION: 17q21.31 microduplication syndrome is a recently described condition associated with a broad clinical spectrum, of which psychomotor delay, behavioral disorders and poor social interaction seem to be the most consistent features. Only seven patients have been reported thus far. All have behavioral disorders reminiscent of the autistic spectrum with intellectual skills ranging from normal to mild intellectual deficiency. Other features are variable with no striking common phenotypic features. CASE STUDY: Here we describe the segregation of 17q21.31 duplication in an Italian family. DISCUSSION: Clinical features and genetic data are reported, and compared with previously reported patients with 17q21.31 microduplication. A comparison of clinical manifestations between deletion and duplication syndromes of the chromosome regione is provided.

Dysmorphologic assessment in 115 Mayer-Rokitansky-Küster-Hauser patients.

Mayer-Rokitansky-Küster-Hauser (MRKH) patients are characterized by congenital aplasia of the uterus and the upper part of the vagina, with normal secondary sexual characteristics. This disorders affects one in 4000-5000 females and it is classified as typical, type I or isolated, and as atypical, type II, manifesting additional malformations. To date, no specific study has addressed the question of facial features in MRKH patients. The aim of this study is to perform a dysmorphological assessment of a large cohort of patients. We studied 115 women referred to our center from 2008 to 2012. Seventy-two percentage (83/115) of our patients showed isolated uterovaginal aplasia (MRKH type I); 32/115 (28%) had other abnormalities including kidney and cardiac defects, skeletal anomalies, and hearing impairment. Auxologic investigations comprised measurements of height, weight, BMI, head circumference, arm span, span to height ratio, hand length, middle finger length, foot length, inner and outer intercanthal distance, and auricle length. All patients had normal measurements, except for the outer canthal distance-inner canthal distance ratio, which was consistent with elongated eyelids. Women with MRKH syndromes do not present a typical facial feature and a dysmorphological examination of all patients seems unnecessary. However, a multidisciplinary approach is useful with respect to explaining the etiology, interpreting test results, and counseling.

Biparental expression of ESX1L gene in placentas from normal and intrauterine growth-restricted pregnancies.

Equivalent levels of X-linked gene products between males and females are reached by means of X chromosome inactivation (XCI). In the human and murine embryonic tissues, both the paternally and maternally derived X chromosomes (X(P) and X(M)) may be inactivated. In murine extra-embryonic tissues, X(P) is imprinted and always silenced; humans, unlike mice, can inactivate the X(M) in extra-embryonic lineages without an adverse outcome. This difference is probably due to the presence of imprinted placental genes on the murine X chromosome, but not on the human homologue, essential for placental development and function. An example is the paternally imprinted Esx1 gene; mice with a null maternally derived Esx1 allele show intrauterine growth restriction (IUGR) because of placental insufficiency. We investigated the imprinting status of the human orthologous Esx1 gene (ESX1L) in placental samples of four normal full-term and 13 IUGR female fetuses, in which we determined the XCI pattern. Our findings demonstrated that IUGR as well as normal placentas display XCI heterogeneity, thus indicating that the IUGR phenotype is not correlated with a preferential pattern of XCI in placentas. Moreover, ESX1L is equally expressed in IUGR and normal placentas, and shows the same methylation pattern in the presence of both random and skewed XCI. These findings provide evidence that ESX1L is not imprinted in human third-trimester placentas and there is no parent-of-origin effect of chromosome X associated with placental insufficiency.

Quantitative DNA methylation analysis improves epigenotype-phenotype correlations in Beckwith-Wiedemann syndrome.

Beckwith-Wiedemann syndrome (BWS) is a rare disorder characterized by overgrowth and predisposition to embryonal tumors. BWS is caused by various epigenetic and/or genetic alterations that dysregulate the imprinted genes on chromosome region 11p15.5. Molecular analysis is required to reinforce the clinical diagnosis of BWS and to identify BWS patients with cancer susceptibility. This is particularly crucial prenatally because most signs of BWS cannot be recognized in utero. We established a reliable molecular assay by pyrosequencing to quantitatively evaluate the methylation profiles of ICR1 and ICR2. We explored epigenotype-phenotype correlations in 19 patients that fulfilled the clinical diagnostic criteria for BWS, 22 patients with suspected BWS, and three fetuses with omphalocele. Abnormal methylation was observed in one prenatal case and 19 postnatal cases, including seven suspected BWS. Seven cases showed ICR1 hypermethylation, five cases showed ICR2 hypomethylation, and eight cases showed abnormal methylation of ICR1 and ICR2 indicating paternal uniparental disomy (UPD). More cases of ICR1 alterations and UPD were found than expected. This is likely due to the sensitivity of this approach, which can detect slight deviations in methylation from normal levels. There was a significant correlation (p<0.001) between the percentage of ICR1 methylation and BWS features: severe hypermethylation (range: 75-86%) was associated with macroglossia, macrosomia, and visceromegaly, whereas mild hypermethylation (range: 55-59%) was associated with umbilical hernia and diastasis recti. Evaluation of ICR1 and ICR2 methylation by pyrosequencing in BWS can improve epigenotype-phenotype correlations, detection of methylation alterations in suspected cases, and identification of UPD.

Fetal DNA in maternal plasma: a noninvasive tool for prenatal diagnosis of beta-thalassemia.

INTRODUCTION: In pregnancy, the discovery of fetal DNA in maternal blood outlined new scenarios for noninvasive prenatal diagnosis of numerous fetal pathological conditions based on a new source of fetal genetic material. Tests on fetal DNA circulating in maternal plasma are expected to replace or reduce invasive procedures, such as chorionic villi sampling and amniocentesis, that are typically carried out late in pregnancy and pose a risk of miscarriage. AREAS COVERED: Nevertheless, at present, no accurate and simple methods for noninvasive prenatal diagnosis of genetic diseases are available, thus preventing a widespread clinical application. EXPERT OPINION: Two highly different sensitive methodologies are reported both allowing the identification of fetal paternally inherited mutations in maternal plasma DNA during the first trimester of pregnancy in a clinically relevant genetic disease. The first one includes mutant enrichment amplification protocols either based on the use of PNA (peptide nucleic acids) or on CO-amplification at Lower Denaturation temperature-PCR (COLD-PCR). In the second approach, an extremely sensitive microarray substrates are exploited which allows the detection of fetal mutated alleles even without the need of any enrichment strategy. Beta-thalassemia has been chosen as a model of clinically relevant genetic disease.

Early manifestations in a cohort of children prenatally diagnosed with 47,XYY. Role of multidisciplinary counseling for parental guidance and prevention of aggressive behavior.

BACKGROUND: An increasing number of foetuses are recognized as having double Y because of the widespread use of prenatal screening using chorionic villus sampling and amniocentesis. 47, XYY karyotype occurs in about one out of 1,000 newborn males, but it is not often detected unless it is diagnosed during prenatal testing. Despite the fact that unbiased follow-up studies demonstrate largely normal post-natal development of young men with 47, XYY, there is a scarcity of controlled studies about the neurological, cognitive and behavioural phenotype which remains the main reason for anxiety and anticipatory negative attitudes of parents. Furthermore, prejudices still exist among professionals and the general population concerning the relationship between this sex chromosome aneuploidy and aggressive and antisocial behaviours. METHODS: We report on the clinical follow-up of children diagnosed prenatally with a 47,XYY karyotype, whose parents received multidisciplinary counselling and support at time of diagnosis. The specific focus of our study is on auxology, facial features, developmental milestones, behaviour, detection of aggressiveness as well as the evaluation of parental attitudes toward prenatal counselling. Clinical evaluations including auxological measurements and dysmorphological descriptions were as conducted on 13 boys aged 9 month -7 years. The Child Behavior Check List test specific for age and a 15 item questionnaire were administered to both parents. An update of ongoing problems was carried out by means of a telephone interview two years later. RESULTS: Our results show that, from birth, weight, height and head circumference were above average values while some facial features such mild hypertelorism are overrepresented when compared to parents' facial features. Language delay was detected in 8 out of 11 children older than 20 months. Parental attitudes were found to be favourable toward prenatal diagnoses of sexual chromosome aneuploidies. CONCLUSIONS: Our data, although limited, is similar to other observational studies, and serves to alert clinicians about opportunities to delineate new and appropriate educational interventions that target the specific learning challenges of XYY boys. Our experience better defines the early manifestation of XYY and should aid those involved in prenatal counselling and paediatric surveillance.

Prenatal manifestation and management of a mother and child affected by spondyloperipheral dysplasia with a C-propeptide mutation in COL2A1: case report.

It is not unusual for patients with "rare" conditions, such as skeletal dysplasias, to remain undiagnosed until adulthood. In such cases, a pregnancy may unexpectedly reveal hidden problems and special needs. A 28 year old primigravida was referred to us at 17 weeks for counselling with an undiagnosed skeletal dysplasia with specific skeletal anomalies suggesting the collagen 2 disorder, spondyloperipheral dysplasia (SPD; MIM 156550).She was counselled about the probability of dominant inheritance and was offered a prenatal diagnosis by sonography. US examination at 17, 18 and 20 weeks revealed fetal macrocephaly, a narrow thorax, and shortening and bowing of long bones. The parents elected to continue the pregnancy. At birth the baby showed severe respiratory distress for four weeks which then resolved. Mutation analysis of both mother and child revealed a hitherto undescribed heterozygous nonsense mutation in the C-propeptide coding region of COL2A1 confirming the diagnosis of SPD while reinforcing the genotype-phenotype correlations between C-propeptide COL2A1 mutations and the SPD-Torrance spectrum. This case demonstrates the importance of a correct diagnosis even in adulthood, enabling individuals affected by rare conditions to be made aware about recurrence and pregnancy-associated risks, and potential complications in the newborn.

Preferential X chromosome loss but random inactivation characterize primary biliary cirrhosis.

UNLABELLED: Recent work has demonstrated enhanced X monosomy in women with primary biliary cirrhosis (PBC) as well as two other female-predominant autoimmune diseases, systemic sclerosis and autoimmune thyroid disease. To further our understanding of these events, we have investigated the mechanisms of X chromosome loss and X chromosome inactivation (XCI) in 166 women with PBC and 226 rigorously age-matched healthy and liver disease controls. X chromosome analysis and determination of loss pattern was performed by quantitative fluorescent polymerase chain reaction (QF-PCR) with 4 X-linked short tandem repeats. Further definition of the XCI was based on analysis of methylation-sensitive restriction sites. Importantly, in PBC the X chromosome loss occurs not only more frequently but also in a preferential fashion. This observation supports our thesis that the enhanced X monosomy involves only one parentally derived chromosome and is not secondary to a constitutive non random pattern of XCI. In fact, in the presence of monosomy, the lost X chromosome is necessarily the inactive homologue. CONCLUSION: The finding that the X chromosome loss is preferential suggests the critical involvement of X chromosome gene products in the female predisposition to PBC and also emphasizes the need to determine the parental origin of the maintained chromosome to investigate the role of imprinting.

Prenatal/neonatal pathology in two cases of Cornelia de Lange syndrome harboring novel mutations of NIPBL.

PURPOSE: This study reviews prenatal findings in two cases with a suspected diagnosis of Cornelia de Lange Syndrome, a multisystem disorder characterized by somatic defects and mental retardation, that were later confirmed by postmortem examination and molecular testing. Although the correlation between the Cornelia de Lange Syndrome genotype and phenotype is still unclear, preliminary data indicate several severe phenotypic features that are likely to be detected prenatally in NIPBL-mutated patients. METHODS: We report on two prenatal/neonatal cases with unusual pathologic findings indicating Cornelia de Lange Syndrome. The first, with suspected Cornelia de Lange Syndrome after a set of typical dysmorphisms was noted by prenatal ultrasound, was confirmed by a physical examination after termination of the pregnancy. The second was diagnosed neonatally on the basis of typical clinical signs. Medical complications led to death within the first month of life. RESULTS: Molecular analysis of NIPBL, the gene that codes for delangin (a component of the cohesin complex), performed postnatally detected two de novo mutations: a missense change (P2056L) in a highly conserved residue and a nonsense alteration (S2490 replaced by a stop codon). CONCLUSION: We suggest that early diagnosis of Cornelia de Lange Syndrome would be made much easier by the assemblage of a set of prenatal diagnostic features and criteria in Cornelia de Lange Syndrome cases that have been confirmed by direct physical and molecular examinations. We also suggest that Cornelia de Lange Syndrome genotype-phenotype correlations need to be extended to prenatal cases.

Three cases with de novo 6q imbalance and variable prenatal phenotype.

We describe two families in which three fetuses had a de novo 6q imbalance and abnormal phenotypes. We determined the boundaries and the parental origin of the chromosomal alterations by segregation analysis using a panel of short tandem repeats (STRs) located on 6q. Cases 1 and 2 (family A) were two sibs with 6q imbalance involving different regions. Case 1 was a female fetus with arthrogryposis, who had a complex rearrangement resulting in two deleted regions (6q22 and 6q25.1-q25.2) and a duplication of 6q23-q25.1. This latter imbalance was reported previously and is associated with joint contractures and short neck, also present in this fetus. The sib (case 2) had intrauterine growth restriction (IUGR) and agenesis of the ductus venosus. This male died shortly after birth; postnatal karyotype and molecular investigations showed a 6q21 de novo deletion. Case 3 (family B) had a prenatally detected deletion of 6q14-q16. Autopsy of the fetus documented minor facial anomalies and contractures of the limbs. All rearrangements were de novo and of paternal origin. Our data and the consistent number of cases of de novo 6q alterations previously reported suggest that chromosome arm 6q could be prone to rearrangements resulting in heterogeneous phenotypes. In family A, chromosome 6q imbalances involving different chromosomal regions were present in two consecutive pregnancies. In such cases counseling should suggest the impossibility of excluding recurrence of a chromosomal imbalance, and should discuss the option of early prenatal diagnosis in subsequent pregnancies.