Anita Wischmeijer

Mowat–Wilson syndrome: Facial phenotype changing with age: Study of 19 Italian patients and review of the literature

Mowat–Wilson syndrome (MWS; OMIM #235730) is a genetic condition caused by heterozygous mutations or deletions of the ZEB2 gene, and characterized by typical face, moderate‐to‐severe mental retardation, epilepsy, Hirschsprung disease, and multiple congenital anomalies, including genital anomalies (particularly hypospadias in males), congenital heart defects, agenesis of the corpus callosum, and eye defects. Since the first delineation by Mowat et al. [Mowat et al. ( 1998 ); J Med Genet 35:617–623], ∼179 patients with ZEB2 mutations, deletions or cytogenetic abnormalities have been reported primarily from Europe, Australia and the United States. Genetic defects include chromosome 2q21–q23 microdeletions (or different chromosome rearrangements) in few patients, and ZEB2 mutations in most. We report on clinical and genetic data from 19 Italian patients, diagnosed within the last 5 years, including six previously published, and compare them with patients already reported. The main purpose of this review is to underline a highly consistent phenotype and to highlight the phenotypic evolution occurring with age, particularly of the facial characteristics. The prevalence of MWS is likely to be underestimated. Knowledge of the phenotypic spectrum of MWS and of its changing phenotype with age can improve the detection rate of this condition.

Loss of the BMP Antagonist, SMOC-1, Causes Ophthalmo-Acromelic (Waardenburg Anophthalmia) Syndrome in Humans and Mice

Ophthalmo-acromelic syndrome (OAS), also known as Waardenburg Anophthalmia syndrome, is defined by the combination of eye malformations, most commonly bilateral anophthalmia, with post-axial oligosyndactyly. Homozygosity mapping and subsequent targeted mutation analysis of a locus on 14q24.2 identified homozygous mutations in SMOC1 (SPARC-related modular calcium binding 1) in eight unrelated families. Four of these mutations are nonsense, two frame-shift, and two missense. The missense mutations are both in the second Thyroglobulin Type-1 (Tg1) domain of the protein. The orthologous gene in the mouse, Smoc1, shows site- and stage-specific expression during eye, limb, craniofacial, and somite development. We also report a targeted pre-conditional gene-trap mutation of Smoc1 (Smoc1tm1a) that reduces mRNA to ∼10% of wild-type levels. This gene-trap results in highly penetrant hindlimb post-axial oligosyndactyly in homozygous mutant animals (Smoc1tm1a/tm1a). Eye malformations, most commonly coloboma, and cleft palate occur in a significant proportion of Smoc1tm1a/tm1a embryos and pups. Thus partial loss of Smoc-1 results in a convincing phenocopy of the human disease. SMOC-1 is one of the two mammalian paralogs of Drosophila Pentagone, an inhibitor of decapentaplegic. The orthologous gene in Xenopus laevis, Smoc-1, also functions as a Bone Morphogenic Protein (BMP) antagonist in early embryogenesis. Loss of BMP antagonism during mammalian development provides a plausible explanation for both the limb and eye phenotype in humans and mice.

Clinical and molecular characterization of 40 patients with classic Ehlers–Danlos syndrome: identification of 18 COL5A1 and 2 COL5A2 novel mutations

BackgroundClassic Ehlers–Danlos syndrome (cEDS) is a rare autosomal dominant connective tissue disorder that is primarily characterized by skin hyperextensibility, abnormal wound healing/atrophic scars, and joint hypermobility. A recent study demonstrated that more than 90% of patients who satisfy all of these major criteria harbor a type V collagen (COLLV) defect.MethodsThis cohort included 40 patients with cEDS who were clinically diagnosed according to the Villefranche nosology. The flowchart that was adopted for mutation detection consisted of sequencing the COL5A1 gene and, if no mutation was detected, COL5A2 analysis. In the negative patients the presence of large genomic rearrangements in COL5A1 was investigated using MLPA, and positive results were confirmed via SNP-array analysis.ResultsWe report the clinical and molecular characterization of 40 patients from 28 families, consisting of 14 pediatric patients and 26 adults. A family history of cEDS was present in 9 patients. The majority of the patients fulfilled all the major diagnostic criteria for cEDS; atrophic scars were absent in 2 females, skin hyperextensibility was not detected in a male and joint hypermobility was negative in 8 patients (20% of the entire cohort). Wide inter- and intra-familial phenotypic heterogeneity was observed. We identified causal mutations with a detection rate of approximately 93%. In 25/28 probands, COL5A1 or COL5A2 mutations were detected. Twenty-one mutations were in the COL5A1 gene, 18 of which were novel (2 recurrent). Of these, 16 mutations led to nonsense-mediated mRNA decay (NMD) and to COLLV haploinsufficiency and 5 mutations were structural. Two novel COL5A2 splice mutations were detected in patients with the most severe phenotypes. The known p. (Arg312Cys) mutation in the COL1A1 gene was identified in one patient with vascular-like cEDS.ConclusionsOur findings highlight that the three major criteria for cEDS are useful and sufficient for cEDS clinical diagnosis in the large majority of the patients. The borderline patients for whom these criteria fail can be diagnosed when minor signs of connective tissue diseases and family history are present and when genetic testing reveals a defect in COLLV. Our data also confirm that COL5A1 and COL5A2 are the major, if not the only, genes involved in cEDS.

Loeys-Dietz syndrome type I and type II: clinical findings and novel mutations in two Italian patients

BackgroundLoeys-Dietz syndrome (LDS) is a rare autosomal dominant disorder showing the involvement of cutaneous, cardiovascular, craniofacial, and skeletal systems. In particular, LDS patients show arterial tortuosity with widespread vascular aneurysm and dissection, and have a high risk of aortic dissection or rupture at an early age and at aortic diameters that ordinarily are not predictive of these events. Recently, LDS has been subdivided in LDS type I (LDSI) and type II (LDSII) on the basis of the presence or the absence of cranio-facial involvement, respectively. Furthermore, LDSII patients display at least two of the major signs of vascular Ehlers-Danlos syndrome. LDS is caused by mutations in the transforming growth factor (TGF) beta-receptor I (TGFBR1) and II (TGFBR2) genes. The aim of this study was the clinical and molecular characterization of two LDS patients.MethodsThe exons and intronic flanking regions of TGFBR1 and TGFBR2 genes were amplified and sequence analysis was performed.ResultsPatient 1 was a boy showing dysmorphic signs, blue sclerae, high-arched palate, bifid uvula; skeletal system involvement, joint hypermobility, velvety and translucent skin, aortic root dilatation, tortuosity and elongation of the carotid arteries. These signs are consistent with an LDSI phenotype. The sequencing analysis disclosed the novel TGFBR1 p.Asp351Gly de novo mutation falling in the kinase domain of the receptor. Patient 2 was an adult woman showing ascending aorta aneurysm, with vascular complications following surgery intervention. Velvety and translucent skin, venous varicosities and wrist dislocation were present. These signs are consistent with an LDSII phenotype. In this patient and in her daughter, TGFBR2 genotyping disclosed in the kinase domain of the protein the novel p.Ile510Ser missense mutation.ConclusionWe report two novel mutations in the TGFBR1 and TGFBR2 genes in two patients affected with LDS and showing marked phenotypic variability. Due to the difficulties in the clinical approach to a TGFBR-related disease, among patients with vascular involvement, with or without aortic root dilatation and LDS cardinal features, genotyping is mandatory to clarify the diagnosis, and to assess the management, prognosis, and counselling issues.

Epilepsy in Mowat-Wilson syndrome: delineation of the electroclinical phenotype.

Mowat–Wilson syndrome (MWS) is a genetic disease caused by heterozygous mutations or deletions of the ZEB2 gene and is characterized by distinctive facial features, epilepsy, moderate to severe intellectual disability, corpus callosum abnormalities and other congenital malformations. Epilepsy is considered a main manifestation of the syndrome, with a prevalence of about 70–75%. In order to delineate the electroclinical phenotype of epilepsy in MWS, we investigated epilepsy onset and evolution, including seizure types, EEG features, and response to anti‐epileptic therapies in 22 patients with genetically confirmed MWS. Onset of seizures occurred at a median age of 14.5 months (range: 1–108 months). The main seizure types were focal and atypical absence seizures. In all patients the first seizure was a focal seizure, often precipitated by fever. The semiology was variable, including hypomotor, versive, or focal clonic manifestations; frequency ranged from daily to sporadic. Focal seizures were more frequent during drowsiness and sleep. In 13 patients, atypical absence seizures appeared later in the course of the disease, usually after the age of 4 years. Epilepsy was usually quite difficult to treat: seizure freedom was achieved in nine out of the 20 treated patients. At epilepsy onset, the EEGs were normal or showed only mild slowing of background activity. During follow‐up, irregular, diffuse frontally dominant and occasionally asymmetric spike and waves discharges were seen in most patients. Sleep markedly activated these abnormalities, resulting in continuous or near‐to‐continuous spike and wave activity during slow wave sleep. Slowing of background activity and poverty of physiological sleep features were seen in most patients. Our data suggest that a distinct electroclinical phenotype, characterized by focal and atypical absence seizures, often preceded by febrile seizures, and age‐dependent EEG changes, can be recognized in most patients with MWS.

Recurrent triploid and dispermic conceptions in patients with NLRP7 mutations

To understand the mechanisms leading to hydatidiform mole formation in patients with NLRP7 mutations, we used a combination of various approaches to characterize five products of conception, from two patients, shown by flow cytometry to contain non-diploid cells. We demonstrate that four of these conceptions are triploid and two of them originated from fertilization with more than one sperm. We show that three of these triploid conceptions fulfill the histopathological criteria of partial hydatidiform mole and one fulfills the histopathological criteria of spontaneous abortion. Our data demonstrate that some oocytes from one patient with NLRP7 mutations are not able to prevent polyspermic fertilization and highlight the importance of using several approaches to characterize the genetic complexity of molar tissues and reproductive wastage. Altogether, our previous and current data show the association of NLRP7 mutations with several types of hydatidiform moles and with triploid spontaneous abortions.

Spontaneous coronary artery dissection in a young woman with Loeys–Dietz syndrome

Spontaneous Coronary Artery Dissection in a Young Woman With Loeys–Dietz Syndrome Rossella Fattori,* Pietro Sangiorgio, Elisabetta Mariucci, Marco Ritelli, Anita Wischmeijer, Cristiano Greco, and Marina Colombi Marfan Center, Cardiothoracovascular Department, University Hospital S.Orsola, Bologna, Italy Invasive Cardiology Laboratory, Department of Cardiology, Maggiore Hospital, Bologna, Italy Division of Biology and Genetics, Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia; Italy Department of Medical Genetics, University Hospital S. Orsola, Bologna, Italy Clinical Genetics Unit, Arcispedale S. Maria Nuova, Reggio Emilia, Italy

Mandibuloacral dysplasia type A in childhood.

Mandibuloacral dysplasia type A (MADA) is characterized by growth retardation, postnatal onset of craniofacial anomalies with mandibular hypoplasia, progressive acral osteolysis, and skin changes including mottled pigmentation, skin atrophy, and lipodystrophy. Owing to its slowly progressive course, the syndrome has been recognized in adults, and pediatric case reports are scarce. We present the clinical case of two children in whom the diagnosis of MADA was made at an unusually early age. A 5‐year‐old boy presented with ocular proptosis, thin nose, and short and bulbous distal phalanges of fingers. A 4‐year‐old girl presented with round face and chubby cheeks, thin nose, bulbous fingertips, and type A lipodystrophy. In both, a skeletal survey showed wormian bones, thin clavicles, short distal phalanges of fingers and toes with acro‐osteolysis. Both children were found to be homozygous for the recurrent missense mutation, c.1580G>A, (p.R527H) in exon 9 of the LMNA gene. Thus, the phenotype of MADA can be manifest in preschool age; diagnosis may be suggested by short and bulbous fingertips, facial features, and lipodystrophy, supported by the finding of acral osteolysis, and confirmed by mutation analysis.

From Whole Gene Deletion to Point Mutations of EP300‐Positive Rubinstein–Taybi Patients: New Insights into the Mutational Spectrum and Peculiar Clinical Hallmarks

Rubinstein–Taybi syndrome (RSTS) is a rare congenital neurodevelopmental disorder characterized by growth deficiency, skeletal abnormalities, dysmorphic features, and intellectual disability. Causative mutations in CREBBP and EP300 genes have been identified in ∼55% and ∼8% of affected individuals. To date, only 28 EP300 alterations in 29 RSTS clinically described patients have been reported. EP300 analysis of 22 CREBBP‐negative RSTS patients from our cohort led us to identify six novel mutations: a 376‐kb deletion depleting EP300 gene; an exons 17–19 deletion (c.(3141+1_3142‐1)_(3590+1_3591‐1)del/p.(Ile1047Serfs*30)); two stop mutations, (c.3829A>T/p.(Lys1277*) and c.4585C>T/p.(Arg1529*)); a splicing mutation (c.1878‐12A>G/p.(Ala627Glnfs*11)), and a duplication (c.4640dupA/p.(Asn1547Lysfs*3)). All EP300‐mutated individuals show a mild RSTS phenotype and peculiar findings including maternal gestosis, skin manifestation, especially nevi or keloids, back malformations, and a behavior predisposing to anxiety. Furthermore, the patient carrying the complete EP300 deletion does not show a markedly severe clinical picture, even if a more composite phenotype was noticed. By characterizing six novel EP300‐mutated patients, this study provides further insights into the EP300‐specific clinical presentation and expands the mutational repertoire including the first case of a whole gene deletion. These new data will enhance EP300‐mutated cases identification highlighting distinctive features and will improve the clinical practice allowing a better genotype–phenotype correlation.

Al-Awadi-Raas-Rothschild (limb/pelvis/uterus-hypoplasia/aplasia) syndrome and WNT7A mutations: genetic homogeneity and nosological delineation.

The Al‐Awadi–Raas‐Rothschild syndrome (AARRS; OMIM 276820) and the Fuhrmann syndrome (FS; OMIM 228930) are distinct limb malformation disorders comprising different degrees of limb aplasia or hypoplasia. In 2006, Woods et al. found different recessive WNT7A mutations in one family segregating the AARRS phenotype and in a second family with FS. To explain the common genetic basis for the two clinically distinct disorders, functional studies were done showing that partial loss of WNT7A function resulted in FS, while complete loss of WNT7A function resulted in the more severe phenotype of AARRS. In spite of the elucidation of the molecular basis of AARRS, there remains to this day considerable diagnostic confusion that has culminated in the lumping of Schinzel phocomelia syndrome with AARRS; however, this phocomelic limb defect is quite different in its clinical aspect and pathogenesis from the limb findings of AARRS. Here, we report on a child with the AARRS phenotype and homozygosity for a non‐conservative E72K mutation in WNT7A, underline the homogeneity of the WNT7A‐associated AARRS phenotype, and propose differential diagnostic criteria for the AARRS reflecting the roles of WNT7A in limb development.