Vera Bianchi

Association of syndromic mental retardation with an Xq12q13.1 duplication encompassing the oligophrenin 1 gene

OPHN1 mutations cause a syndromic form of mental retardation (MR) characterized by cerebellar hypoplasia, early hypotonia, motor and speech delay, with occasional seizures and strabismus. Here we report on a familial chromosome duplication spanning about 800 Kb of Xq12q13.1, associated with MR and a distinctive phenotype in the affected male, but not in his heterozygous mother. The parents were healthy and non‐consanguineous with a history of three pregnancies. The first resulted in the birth of a boy with MR, motor impairment and seizures. The second pregnancy was terminated because of trisomy 18. At the time of the third, the first affected boy was analyzed by array‐CGH, which revealed a 800 Kb duplication at Xq12q13.1, encompassing three genes, including OPHN1. This mutation was inherited from his healthy mother and was not present in any of the three maternal brothers. To our knowledge this is the first report of a clinical phenotype associated with duplication of Xq12q13.

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.

Clinical follow-up of young adults affected by Williams syndrome: Experience of 45 Italian patients†

Williams–Beuren syndrome (WBS) is a multisystem disorder that requires ongoing management by a primary care physician familiar with the natural history and specific medical problems associated with the condition. While the natural history of the disease during infancy is well known, data about the adult WBS population have been published only in the last few years, and show a wide range of medical, neurological, and psychiatric problems. We investigated 45 young adult WBS patients (mean age 23 years, range 17–39 years) using a well‐coordinated team which included a cardiologist, a nephrologist, an ophthalmologist, an endocrinologist, a gastroenterologist, orthodontist, and orthopedist. Here we describe the clinical features and medical complications in this cohort of patients. Most patients demonstrated a high frequency of multiple organ systems complications, in particular, abnormal body habitus; cardiovascular disease, and hypertension; sensorineural hearing loss; gastrointestinal symptoms including diverticular disease and abnormal glucose tolerance. We offer some suggestions for clinical monitoring which we propose will be useful in the overall care of adults with WBS.

An interactive computer program can effectively educate potential users of cystic fibrosis carrier tests

The demand for cystic fibrosis (CF) carrier testing is steadily growing, not only from individuals with raised a priori carrier risk, but also from the general population. This trend will likely exceed the availability of genetic counselors, making it impossible to provide standard face‐to‐face genetic counseling to all those asking for the test. In order to reduce the time needed to educate individuals on the basics of the disease, its genetic transmission, and carrier testing peculiarities, we developed an educational method based on an interactive computer program (IC). To assess the effectiveness of this program and to compare it to a classical genetic counseling session, we conducted a comparative trial. In a population setting of people undergoing assisted reproduction, 44 individuals were randomly assigned to either receiving standard one‐on‐one genetic counseling or education by the IC program. We measured pre‐ and post‐intervention knowledge about CF genetic transmission and carrier testing. Starting from an equivalent baseline of correct answers to a specially designed multiple‐choice questionnaire (47% in the counselor group and 45% in the computer group) both groups showed a highly significant and similar increase (reaching 84% in the counselor group and 85% in the computer group). The computer program under evaluation can successfully educate individuals considering genetic testing for CF.

Prevalence of diabetes and pre‐diabetes in a cohort of Italian young adults with Williams syndrome

Williams syndrome (WS) is a rare, multisystemic genomic disorder showing a high prevalence of impaired glucose metabolism in adulthood. The reason for this association is unknown, though hemizygosity for genes mapping to the WS chromosome region has been implicated. Twenty‐two Italian young adults with WS (13 females, 9 males) were studied. A 75u2009g oral glucose tolerance test (OGTT) was performed and β‐cell function was estimated with Homeostasis Model Assessment (HOMA)‐B%, Insulinogenic Index, and corrected insulin response whereas insulin sensitivity was assessed with HOMA‐Insulin Resistance Index, Quantitative Insulin Check Index, and composite Insulin Sensitivity Index. One patient had known diabetes mellitus (DM), whereas impaired glucose tolerance (IGT) was diagnosed in 12 patients and DM in one (63.6% prevalence of impaired glucose metabolism). IGT patients were more insulin resistant than those with normal glucose tolerance (NGT), whereas β‐cell function was unchanged or increased. Islet autoimmunity was absent. Logistic regression showed that impaired glucose metabolism was not associated with age, body mass index (BMI), or family history of DM. β‐cell function, insulin sensitivity, and post‐load insulin levels did not differ between WS patients with NGT and healthy controls comparable for gender, age, and BMI, though WS–NGT patients had higher post‐load glucose values. These data confirm the high prevalence of impaired glucose metabolism in WS young adults, thus suggesting the need for screening these patients with OGTT. IGT is associated with reduced insulin sensitivity, but not with impaired β‐cell function, islet autoimmunity, and traditional risk factors for type 2 DM.

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.

Prenatal phenotype of Nager syndrome and Rodriguez syndrome: variable expression of the same entity?

Medical Genetics, University of Pavia, Pavia, Medical Genetics Unit, Obstetrics and Gynecology Unit, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan and Pathology Unit, AO Vimercate, Vimercate, Italy Correspondence to Barbara Gentilin, MD, Medical Genetics Unit, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Commenda 12, Milan 20122, Italy Tel: + 39 025 503 2941; fax: + 39 025 503 2353; e-mail: barbara.gentilin@libero.it

Autosomal Dominant Diseases are too Often Overlooked in the Parents of Affected Children: Report of Six Cases

Clinical genetics is the discipline which deals with hereditary diseases and implies a strong diagnostic approach without which all information conveyed by the counselling process has insecure foundation and the estimation of recurrence risk within the family may be misinterpreted. nThe ideal time for having a genetic counselling is before pregnancy. In this case the subsequent genetic evaluation and counselling may lead to the definition of a reproductive risk and thus to an early, even prenatal diagnosis in the offspring. However in some cases genetic conditions are under-recognized in the adult age and people are not referred to genetic services. This happens because of a variety of reasons both related to the health professionals (non-habit to the pre-conceptional genetic counselling, lack of attention/information on genetic themes, diagnostic difficulties related to the variability of gene expression, incomplete penetrance and late onset conditions) and to the patient’s psychological status, for example denial mechanisms. nSix cases are presented in which a correct diagnosis in one parent was reached after the identification of a rare disease in the child with severe psychological and social consequences. nObviously the lack of the correct diagnosis in the parent implied that he/she was not only uninformed about the presence of the increased reproductive risk, but also unaware of the clinical variability of the condition. Anger and frustration was present in all affected parents asking why their family doctors never suspected the condition which, afterwards, seemed quite obvious. Legal actions were started in two out of six cases. nEstablishing the correct diagnosis, or at least the suspicion of a genetic disease, is therefore a priority that may be not considered an exclusive responsibility of the geneticist, but ideally involves other medical figures, for example primary care physician, pediatricians or other medical specialists who see a patient with a condition.

When and how ruling out cystic fibrosis in adult patients with bronchiectasis

BackgroundBronchiectasis is the final result of different processes and most of the guidelines advocate for a careful evaluation of those etiologies which might be treated or might change patients’ management, including cystic fibrosis (CF).Main bodyCFTR mutations have been reported with higher frequency in bronchiectasis population. Although ruling out CF is considered as a main step for etiological screening in bronchiectasis, CF testing lacks of a standardized approach both from a research and clinical point of view. In this review a list of most widely used tests in CF is provided.ConclusionsExclusion of CF is imperative for patients with bronchiectasis and CFTR testing should be implemented in usual screening for investigating bronchiectasis etiology. Physicians taking care of bronchiectasis patients should be aware of CFTR testing and its limitations in the adult population. Further studies on CFTR expression in human lung and translational research might elucidate the possible role of CFTR in the pathogenesis of bronchiectasis.

2q33.1q34 Deletion in a Girl with Brain Anomalies and Anorectal Malformation

2q33 deletions are considered to constitute a distinct clinical entity (Glass syndrome or 2q33 microdeletion syndrome) with a characteristic phenotype. Most patients have moderate to severe developmental delay, speech delay, a particular behavioural phenotype, feeding problems, growth restriction, a typical facial appearance, thin and sparse hair, tooth abnormalities, and skeletal anomalies. Here, we report on a patient with a 2q33.1q34 deletion spanning 8.3 Mb of genomic DNA. Although her clinical features are very reminiscent of the 2q33 microdeletion syndrome, she also presented with brain and anorectal malformations. Based on the present and published patients with 2q33 deletions, we suggest that the critical region for the Glass syndrome may be larger than initially proposed. Moreover, we suggest that brain abnormalities might be an additional feature of the 2q33 microdeletion syndrome, but that anorectal malformation is likely not a key marker.