Rita Mingarelli

22q11 deletions in isolated and syndromic patients with tetralogy of Fallot

Tetralogy of Fallot (TF) is a congenital conotruncal heart defect commonly found in DiGeorge (DGS) and velo-cardio-facial (VCFS) syndromes. The deletion of chromosome 22q11 (de122q11) is a well established cause of DGS and VCFS, and it has been demonstrated also in sporadic or familial cases of TF. In order to investigate the prevalence of de122q11 in patients with TF, we analyzed the DNA of 137 consecutive patients with syndromic and isolated TF, using the HD7k probe, which detects hemizygosity for the D22S134 locus. De122q11 has been detected in 11/26 (42%) syndromic patients. Evidence for hemizygosity was obtained in all patients with DGS and in 8/15 patients with VCFS. None of the 107 patients with isolated TF had de122q11. Our experience suggests that children with TF and de122q11 always present major or minor extracardiac anomalies. These features, including subtle facial dysmorphisms, should be checked routinely in patients with TF and other conotruncal heart defects.

A locus for autosomal dominant keratoconus maps to human chromosome 3p14–q13

Keratoconus (OMIM148300) is a bilateral, non-inflammatory, slowly progressive, corneal ectasia that is a major cause of corneal transplant. Characteristically, the cornea becomes thin and conical, with myopia and irregular astigmatism that leads to vision impairment. The incidence of keratoconus is between 50 and 230 per 100 000, with remarkable differences between ethnic groups.1 Although the pathogenesis of keratoconus still is unknown, little doubt exists about an underlying genetic background. A positive family history is found in 6–8% of patients with keratoconus, and concordance is high among monozygotic twins.1,2 In rare instances, keratoconus is inherited either as a mendelian trait or is associated with a genetic disorder (for example, Down syndrome, Leber’s amaurosis, or connective tissue diseases). For most patients, however, the disease is sporadic.3 The lack of multiple familial cases is a major obstacle to linkage analysis. To date, three loci have been associated with keratoconus, none of them through a genomewide search in a single informative family. A putative 6.8 cM locus was identified in a family affected by keratoconus by direct scan of chromosome 21 only, while an association at 20q12 was found in seven related Tasmanian patients.4,5 More recently, a non-parametric linkage analysis in 20 Finnish small pedigrees with autosomal dominant keratoconus identified a third locus to chromosome 16q.6 Finally, two distinct heterozygous mutations in the VSX1 homeobox gene were identified with a candidate gene approach in two families affected by keratoconus.7 Recent advances in computerised topographic diagnostic techniques enable higher accuracy in the diagnosis of keratoconus, including forme fruste , which eases the identification of extensive families affected by keratoconus. We describe an Italian family with autosomal dominant pure keratoconus and the localisation of a novel keratoconus locus to chromosome 3p14–q13. ### Clinical studies We identified an Italian pedigree with autosomal …

Evidence for differential S100 gene over-expression in psoriatic patients from genetically heterogeneous pedigrees.

Abstract. Psoriasis is an inflammatory skin disorder characterised by keratinocyte hyper-proliferation and altered differentiation. To date, linkage analyses have identified at least seven distinct disease susceptibility regions (PSORS1–7). The PSORS4 locus was mapped by our group to chromosome 1q21, within the Epidermal Differentiation Complex. This cluster contains 13 genes encoding S100 calcium-binding proteins, some of which (S100A7, S100A8 and S100A9) are known to be up-regulated in individual patient keratinocytes. In this study, we analysed S100 gene expression in psoriatic individuals from families characterised by linkage studies. We first selected individuals from two large pedigrees, one of which was linked to the 1q21 locus, whereas the other was unlinked to that region. We studied the expression of 12 S100 genes, by semi-quantitative RT-PCR and Northern blot. These analyses demonstrated up-regulation of S100A8, S100A9 and, to a lesser extent, S100A7 and S100A12, only in the 1q21 linked family. We subsequently analysed S100A7, S100A8, S100A9 and S100A12 in three additional samples and were able to confirm S100A8/S100A9-specific over-expression in 1q-linked pedigrees. Thus, our data provide preliminary evidence for a locus-specific molecular mechanism underlying psoriasis susceptibility.

A quarter of men with idiopathic oligo-azoospermia display chromosomal abnormalities and microdeletions of different types in interval 6 of Yq11.

Cytogenetic investigations and molecular analysis of the Y chromosome by the polymerase chain reaction amplification of sequence-tagged sites (STS-PCR) technique were performed in 126 patients affected by idiopathic oligo-azoospermia following accurate selection of cases. Seventeen patients evidenced an abnormal karyotype. Fourteen patients with a normal karyotype had microdeletions of the Y chromosome within interval 6. In azo-ospermic patients microdeletions were scattered along different subintervals, while in oligozoospermic patients they were clustered in subinterval 6E. The size of the deletion was not apparently related to the severity of the disease. These results suggest that cytogenetic analysis and the STS-PCR technique can detect a genetic cause of infertility in about one-quarter of patients with idiopathic oligo-azoospermia.

Associated cardiac anomalies in isolated and syndromic patients with tetralogy of fallot

To detect in children with tetralogy of Fallot (ToF) the prevalence of associated cardiac anomalies in syndromic and isolated cases, the additional cardiac defects of 150 consecutive patients with ToF (102 isolated and 48 syndromic cases) were evaluated by review of echocardiographic, angiocardiographic, and surgical reports. Syndromic patients were classified into groups with branchial arch defects, Down syndrome, and other genetic conditions. ToF is significantly associated with additional cardiac malformations in patients with branchial arch (11 of 21, p <0.01) and Down (10 of 20, p <0.0001) syndromes. The subarterial ventricular septal defect with deficiency of the infundibular septum (4 of 21, p <0.01) and the right aortic arch (6 of 21, p <0.05) were prevalent in patients with branchial arch syndromes, whereas atrioventricular canal (10 of 20, p <0.0001) was associated with ToF in patients with Down syndrome. Peculiar anatomic cardiac patterns are present in children with ToF and may alert the cardiologist to look at additional cardiac anomalies. Moreover, the presence of some associated cardiac anomalies may suggest careful clinical evaluation for genetic syndromes.

Analysis of the elastin gene in 60 patients with clinical diagnosis of Williams syndrome

Williams syndrome (WS) is caused by deletion of the elastin (ELN) gene. We have analyzed an intragenic restriction fragment length polymorphism (RFLP) and the gene dosage of ELN using a new probe (FP4) in a series of 60 sporadic patients with a clinical diagnosis of WS. Deletion of the ELN gene was shown in 54 cases, while clinical revaluation of the 6 patients without the deletion did not confirm the diagnosis of WS. These results support the genetic homogeneity of WS, and the high accuracy of ELN molecular analysis, which can be confidenty used for providing genetic counselling to WS families.

A novel PTPN11 gene mutation bridges Noonan syndrome, multiple lentigines/LEOPARD syndrome and Noonan-like/multiple giant cell lesion syndrome

Noonan (NS) and multiple lentigines/LEOPARD syndromes (LS) have proved to be associated with distinct PTPN11 mutations. Noonan-like/multiple giant cell lesion syndrome (NLS) is a rare disease, characterised by short stature, facial dysmorphisms, congenital heart defect (CHD) and central giant cell lesions. PTPN11 gene mutations have been reported in a single NLS family and two sporadic patients. Here we report a patient with a complex phenotype progressing throughout the years from NS at birth towards LS and NLS. PTPN11 gene analysis disclosed a novel missense mutation (Ala461Thr) in exon 12, affecting the consensus sequence of the SHP2-active site. This observation joins together NS and LS to NLS into a unique genetic defect, broadening the clinical and molecular spectrum of PTPN11-related disorders.

Majewski osteodysplastic primordial dwarfism type II (MOPD II) complicated by stroke: clinical report and review of cerebral vascular anomalies.

We report on a 2 9/12‐year‐old boy with disproportionate short stature, microcephaly, subtle craniofacial dysmorphisms, and generalized skeletal dysplasia, who developed a left hemiparesis. Brain neuroimaging disclosed a complex cerebral vascular anomaly (CVA) with stenosis of the right anterior cerebral artery and telangiectatic collateral vessels supplying the cerebral cortex, consistent with moyamoya disease. Based on clinical and skeletal features, a diagnosis of Majewski osteodysplastic primordial dwarfism type II (MOPD II) was established. Review of 16 published patients with CVA affected by either Seckel syndrome or MOPD II suggested that CVA is preferentially associated to the latter subtype affecting about 1/4 of the patients.

Antenatal presentation of the oculo-auriculo-vertebral spectrum (OAVS)†

We describe a fetus with abnormal ultrasound (US) imaging at 20 weeks showing hydrocephalus and radial aplasia. Post‐mortem examination followed pregnancy termination and confirmed the diagnosis of oculo‐auriculo‐vertebral spectrum (OAVS). To delineate the pattern of prenatal features in OAVS, we reviewed 20 published fetuses showing abnormal US and/or magnetic resonance imaging. Gestational age at diagnosis ranged from 14 to 34–35 weeks. Cephalic abnormalities were found in only 52.4% (i.e., micro/anophthalmia, ear anomalies, hemifacial microsomia, and facial cleft). CNS defects occurred in 47.6% (i.e., hydrocephalus, occipital encephalocele, cerebellar hemisphere/vermis hypoplasia, and lipoma of the corpus callosum), together with abnormal amniotic fluid volume (AFV), either poly‐ or oligohydramnios. Nineteen percent had congenital heart disease, mainly atrioventricular septal defect. Hydroureteronephrosis, radial aplasia, lung, and kidney agenesis were additional findings. Recurrent patterns of anomalies included multiple asymmetric facial lesions (i.e., hemifacial microsomia, ipsilateral micro/anophthalmia, malformed ear) and CNS (particularly hydrocephalus) plus AFV abnormalities. In addition, prognosis of prenatally detected OAVS patients resulted more severe than generally observed in this condition.

Syndromic craniosynostosis due to complex chromosome 5 rearrangement and MSX2 gene triplication

Craniosynostosis is a common birth defect (∼1/3,000 births) resulting from chromosome imbalances, gene mutations or unknown causes. We report a 6‐month‐old female with multiple sutural synostosis and prenatal onset growth deficiency, developmental delay, facial dysmorphism, congenital heart defect, and inguinal hernia. An integrated approach of standard cytogenetics, mBAND, locus‐specific FISH, and 75 kb resolution array‐CGH disclosed a complex chromosome 5 rearrangement, resulting in 3 paracentric inversions, 2 between‐arm insertions, and partial duplication of 5q35. An extra copy of the MSX2 gene, which maps within the duplicated segment and is mutated in Boston‐type craniosynostosis, was confirmed by molecular cytogenetic studies. Our study confirms that early fusion of cranial sutures commonly observed in the dup(5q) syndrome is caused by triplication of the MSX2 gene and strongly supports the crucial role of this gene in the development of craniofacial structures.