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Disciglio V.,University of Siena | Rizzo C.L.,University of Siena | Mencarelli M.A.,University of Siena | Mucciolo M.,University of Siena | And 22 more authors.
American Journal of Medical Genetics, Part A | Year: 2014

Phelan-McDermid syndrome (22q13.3 deletion syndrome) is a contiguous gene disorder resulting from the deletion of the distal long arm of chromosome 22. SHANK3, a gene within the minimal critical region, is a candidate gene for the major neurological features of this syndrome. We report clinical and molecular data from a study of nine patients with overlapping interstitial deletions in 22q13 not involving SHANK3. All of these deletions overlap with the largest, but not with the smallest deletion associated with Phelan-McDermid syndrome. The deletion sizes and breakpoints varied considerably among our patients, with the largest deletion spanning 6.9Mb and the smallest deletion spanning 2.7Mb. Eight out of nine patients had a de novo deletion, while in one patient the origin of deletion was unknown. These patients shared clinical features common to Phelan-McDermid syndrome: developmental delay (11/12), speech delay (11/12), hypotonia (9/12), and feeding difficulties (7/12). Moreover, the majority of patients (8/12) exhibited macrocephaly. In the minimal deleted region, we identified two candidate genes, SULT4A1 and PARVB (associated with the PTEN pathway), which could be associated in our cohort with neurological features and macrocephaly/hypotonia, respectively. This study suggests that the haploinsufficiency of genes in the 22q13 region beside SHANK3 contributes to cognitive and speech development, and that these genes are involved in the phenotype associated with the larger Phelan-McDermid syndrome 22q13 deletions. Moreover, because the deletions in our patients do not involve the SHANK3 gene, we posit the existence of a new contiguous gene syndrome proximal to the smallest terminal deletions in the 22q13 region. © 2014 Wiley Periodicals, Inc.


Van Bon B.W.M.,Radboud University Nijmegen | Koolen D.A.,Radboud University Nijmegen | Brueton L.,University of Birmingham | McMullan D.,University of Birmingham | And 27 more authors.
European Journal of Human Genetics | Year: 2010

Six submicroscopic deletions comprising chromosome band 2q23.1 in patients with severe mental retardation (MR), short stature, microcephaly and epilepsy have been reported, suggesting that haploinsufficiency of one or more genes in the 2q23.1 region might be responsible for the common phenotypic features in these patients. In this study, we report the molecular and clinical characterisation of nine new 2q23.1 deletion patients and a clinical update on two previously reported patients. All patients were mentally retarded with pronounced speech delay and additional abnormalities including short stature, seizures, microcephaly and coarse facies. The majority of cases presented with stereotypic repetitive behaviour, a disturbed sleep pattern and a broad-based gait. These features led to the initial clinical impression of Angelman, Rett or Smith-Magenis syndromes in several patients. The overlapping 2q23.1 deletion region in all 15 patients comprises only one gene, namely, MBD5. Interestingly, MBD5 is a member of the methyl CpG-binding domain protein family, which also comprises MECP2, mutated in Rett's syndrome. Another gene in the 2q23.1 region, EPC2, was deleted in 12 patients who had a broader phenotype than those with a deletion of MBD5 only. EPC2 is a member of the polycomb protein family, involved in heterochromatin formation and might be involved in causing MR. Patients with a 2q23.1 microdeletion present with a variable phenotype and the diagnosis should be considered in mentally retarded children with coarse facies, seizures, disturbed sleeping patterns and additional specific behavioural problems. © 2010 Macmillan Publishers Limited All rights reserved.


Grillo L.,Laboratory of Genetic Diagnosis | Reitano S.,Unit of Pediatrics and Medical Genetics | Belfiore G.,Unit of Psychology | Spalletta A.,Laboratory of Genetic Diagnosis | And 6 more authors.
European Journal of Medical Genetics | Year: 2010

We report on a 7-year-old girl with severe mental retardation (MR), autism, micro-brachycephaly, generalized muscle hypotonia with distal hypotrophy of lower limbs, scoliosis and facial dysmorphisms. Array-CGH analysis identified a 1.1 Mb deletion of chromosome Xq22.1. Further analysis demonstrated that the deletion was inherited from her mother who showed mild MR, short stature, brachycephaly, epilepsy and a Borderline Personality Disorder. Microsatellite segregation analysis revealed that the rearrangement arose de novo in the mother on the paternal X chromosome. The deleted Xq22.1 region contains part of the NXF gene cluster which is involved in mRNA nuclear export and metabolism. Among them, the NXF5 gene has already been linked to mental retardation whereas NXF2 protein has been recently found to be partner of FMRP in regulating Nxf1 mRNA stability in neuronal cells. The dosage imbalance of NXF5 and NXF2 genes may explain the severe phenotype in our patient. © 2010 Elsevier Masson SAS. All rights reserved.


Mencarelli M.A.,University of Siena | Tassini M.,University of Siena | Pollazzon M.,University of Siena | Vivi A.,University of Siena | And 10 more authors.
American Journal of Medical Genetics, Part A | Year: 2011

Creatine deficiency syndrome due to mutations in X-linked SLC6A8 gene results in nonspecific intellectual disability (ID). Diagnosis cannot be established on clinical grounds and is often based on the assessment of brain creatine levels by magnetic resonance spectroscopy (MRS). Considering high costs of MRS and necessity of sedation, this technique cannot be used as a first level-screening test. Likewise, gene test analysis is time consuming and not easily accessible to all laboratories. In this article feasibility of urine analysis (creatine/creatinine (Cr/Crn) ratio) performed by nuclear magnetic resonance (NMR) as a first level-screening test is explored. Before running a systematic selection of cases a preliminary study for further molecular analysis is shown. NMR urine spectra (n=1,347) of male patients with an ID without a clinically recognizable syndrome were measured. On the basis of abnormal Cr/Crn ratio, three patients with the highest values were selected for molecular analysis. A confirmatory second urine test was positive in two patients and diagnosis was further confirmed by a decreased brain creatine level and by SLC6A8 gene analysis. A de novo mutation was identified in one. Another patient inherited a novel mutation from the mother who also has a mild ID. A repeat urine test was negative in the third patient and accordingly creatine level in the brain and SLC6A8 gene analysis both gave a normal result. We conclude that Cr/Crn ratio measured by NMR for male patients represents a rapid and useful first level screening test preceding molecular analysis. © 2011 Wiley-Liss, Inc.


Concolino D.,University of Catanzaro | Iembo M.A.,University of Catanzaro | Moricca M.T.,University of Catanzaro | Rapsomaniki M.,University of Catanzaro | And 5 more authors.
European Journal of Medical Genetics | Year: 2012

We report a new case of 8q interstitial duplication in a patient with dysmorphic features, umbilical hernia, cryptorchidism, short stature, congenital heart defect and mild mental retardation (MR). Chromosome analysis with high resolution QFQ bands showed 46,XY, 8q+, which was interpreted as a partial duplication of the distal long arm of chromosome 8 (q22 → qter). This chromosomal aberration was further characterized using fluorescence in situ hybridization (FISH) analyses with multiple DNA probes and array-CGH (Comparative Genomic Hybridization) experiment which demonstrated a de novo direct duplication (8)(q22.2-q24.3). We have compared this case with other partially trisomic 8q patients reported in literature and highlighted the common clinical features in 8q22-8q24 duplication syndrome. © 2011.


PubMed | Laboratory of Genetic Diagnosis
Type: Case Reports | Journal: European journal of medical genetics | Year: 2010

We report on a 7-year-old girl with severe mental retardation (MR), autism, micro-brachycephaly, generalized muscle hypotonia with distal hypotrophy of lower limbs, scoliosis and facial dysmorphisms. Array-CGH analysis identified a 1.1 Mb deletion of chromosome Xq22.1. Further analysis demonstrated that the deletion was inherited from her mother who showed mild MR, short stature, brachycephaly, epilepsy and a Borderline Personality Disorder. Microsatellite segregation analysis revealed that the rearrangement arose de novo in the mother on the paternal X chromosome. The deleted Xq22.1 region contains part of the NXF gene cluster which is involved in mRNA nuclear export and metabolism. Among them, the NXF5 gene has already been linked to mental retardation whereas NXF2 protein has been recently found to be partner of FMRP in regulating Nxf1 mRNA stability in neuronal cells. The dosage imbalance of NXF5 and NXF2 genes may explain the severe phenotype in our patient.

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