1p31.1 microdeletion including only NEGR1 gene in two patients

Neuronal growth regulator 1 (NEGR1), a member of the immunoglobulin superfamily cell adhesion molecule subgroup IgLON, has been involved in neuronal growth and connectivity. Genetic variants, in or near the NEGR1 locus, have been associated with obesity and, more recently, with learning difficulties, intellectual disability, and psychiatric disorders. Here, we described the only second report of NEGR1 gene disruption in 1p31.1 microdeletion in two patients. Patient 1 is a 14-year-old female with neurological and psychiatric features present also in her family. Patient 2 is a 5-month-old infant showing global hypotonia as unique neurological features till now. This patient also carries 7p22.1 duplication, of paternal origin, that could be responsible for some malformations present in the child. We hypothesize a role of NEGR1 in producing the phenotype of our patients and compare them with other cases previously reported in the literature and DECIPHER database to better identify a possible genotype-phenotype correlation.

'Distal 16p12.2 microdeletion' in a patient with autosomal recessive deafness-22

The 16p12.2 chromosome band contains three large segmental duplications: BP1, BP2 and BP3, providing a substrate for recombination and recurrent chromosomal rearrangements. The '16p12.2 microdeletion' is a recurrent deletion comprised between BP2 and BP3, associated with variable clinical findings. We identified a heterozygous 16p12.2 microdeletion spanning between BP1 and BP2 in a child evaluated for short stature and mild dyslexia. Unexpectedly, the mother carried the same deletion in the homozygous state and suffered from severe hearing loss. Detailed family history revealed consanguinity of the maternal grandparents. The 16p12.2 microdeletion is a rare condition and contains only three genes: METTL9, IGSF6 and OTOA of which the OTOA is considered responsible for DFNB22 hearing loss (MIM: 607039) under its homozygous condition. A number of OTOA mutations have been described, whereas very few cases of a 16p12.2 microdeletion similar to that observed in our family have been reported. In conclusion, we describe a rare 'distal 16p12.2microdeletion' widening the phenotypic spectrum associated with the recurrent 16p12.2 microdeletion and support the causative role of OTOA microdeletion in hearing impairment.

Clinical and Molecular Characterization of Two Patients with CNTN6 Copy Number Variations

Submicroscopic chromosomal alterations usually involve different protein-coding genes and regulatory elements that are responsible for rare contiguous gene disorders, which complicate the understanding of genotype-phenotype correlations. Chromosome band 3p26.3 contains 3 genes encoding neuronal cell adhesion molecules: CHL1, CNTN6, and CNTN4. We describe 2 boys aged 8 years and 11 years mainly affected by intellectual disability and autism spectrum disorder, who harbor a paternally inherited 3p26.3 microdeletion and a 3p26.3 microduplication, respectively. Both anomalies involved only the CNTN6 gene, which encodes contactin 6, a member of the contactin family (MIM 607220). Contactins show pronounced brain expression and function. Interestingly, phenotypes in reciprocal microdeletions and microduplications of CNTN6 are very similar. In conclusion, our data, added to those reported in the literature, are particularly significant for understanding the pathogenic effect of single gene dosage alterations. As for other recurrent syndromes with variable phenotype, these findings are challenging in genetic counselling because of an evident variable penetrance.

Controlled ovarian stimulation and IVF pregnancy in a trisomy X carrier with associated hypogonadotropic hypogonadism

We describe successful controlled ovarian stimulation (COS) and the first known IVF pregnancy in a trisomy X carrier with associated hypogonadotropic hypogonadism (HH) linked to a chromosome 4 double mutation in the allele of the Gonadotropins Releasing Hormone receptor (GnRHr) gene. Previous administration of low dose of gonadotropins, as recommended in patients with HH, led to poor follicular recruitment. Since trisomy X is a risk factor for diminished ovarian reserve (DOR) and premature ovarian insufficiency (POI), higher doses of gonadotropins led to better ovarian response. The report readknowledges the importance of a correct genetic evaluation in a competent laboratory as a reliable base for treatment planning in this kind of patients.

Characterization of the Phenotype Associated with Microduplication Reciprocal to NF1 Microdeletion Syndrome

17q11.2 microduplication syndrome is a recently described relatively rare condition associated with a nonspecific phenotype. Intellectual disability, developmental delay, and dysmorphisms are the only clinical features common to a majority of cases. Seventeen patients have been reported so far. Here, we present another patient with 17q11.2 duplication and no signs of neurofibromatosis type 1, identified by array-CGH. We compared clinical features and genetic data with those of previously reported patients with 17q11.2 microduplications. We also analyzed the gene content of the duplicated region in order to investigate the possible role of specific genes in the clinical phenotype of our patient.

Hypogonadotropic hypogonadism in a trisomy X carrier: phenotype description and genotype correlation

We report on a 31-year old female who presented at genetic counseling for a small uterus, secondary amenorrhea and sterility. Gonadotropic hormone levels were low, suggesting a Hypogonadotropic Hypogonadism (HH) condition. Cytogenetic analysis demonstrated the presence of Trisomy X associated to an interstitial deletion of chromosome 4q13.2, resulting in the complete loss of a copy of the GNRHR gene. As GNRHR is known to be responsible for an autosomal recessive form of HH, we checked the status of the undeleted allele and we found the Q106R substitution. In conclusion, the results of our cytogenetic and molecular analyses have allowed us to clarify the etiology of the patient's condition.

Clinical and molecular delineation of a 16p13.2p13.13 microduplication

The 16p13.3p13.1 region has been reported as a "critical" hotspot region for recurrent microdeletions/duplications, which may contribute to epilepsy, learning difficulties and facial dysmorphisms. Cytogenetic and array-CGH analyses were performed because of the clinical characteristics of the patient. The girl showed de novo 16p13.3p13.13 duplication spanning a region of ∼5.3 Mb. She presented brain anomalies, intellectual disability, epilepsy, facial and vertebral dysmorphisms. To our knowledge, this is the first reported case of 16p13.3p13.13 duplication; only three patients with an overlapping deletion in 16p13.2p13.13 were previously described. The duplicated region contains 21 OMIM genes and, six of them (RBFOX1, TMEM114, ABAT, PMM2, GRIN2A and, LITAF) were found to be associated with known diseases. Although no duplication of these genes has been described in the literature, we discuss here if they had some role in determining phenotype of our patient.

Interstitial 7q31.1 copy number variations disrupting IMMP2L gene are associated with a wide spectrum of neurodevelopmental disorders

Background

Since the introduction of the array-CGH technique in the diagnostic workup of mental retardation, new recurrent copy number variations and novel microdeletion/microduplication syndromes were identified. These findings suggest that some genomic disorders have high penetrance but a wide range of phenotypic severity.

Results

We present the clinical and molecular description of four unrelated patients affected by neurodevelopmental disorders and overlapping 7q31.1 microdeletion/microduplication, identified by array-CGH and involving only part of the IMMP2L gene.

Conclusion

IMMP2L encodes an inner mitochondrial membrane protease-like protein, which is required for processing of cytochromes inside mitochondria. Numerous studies reported that this gene is implicated in behavioural disorders such as autistic spectrum disorders, attention-deficit hyperactivity disorders, and Gilles de la Tourette syndrome. We discuss the functions of the gene suggesting that IMMP2L may act as risk factor for neurological disease.

Mutations in SOX17 are associated with congenital anomalies of the kidney and the urinary tract

Congenital anomalies of the kidney and the urinary tract (CAKUT) represent a major source of morbidity and mortality in children. Several factors (PAX, SOX,WNT, RET, GDFN, and others) play critical roles during the differentiation process that leads to the formation of nephron epithelia. We have identified mutations in SOX17, an HMG-box transcription factor and Wnt signaling antagonist, in eight patients with CAKUT (seven vesico-ureteric reflux, one pelvic obstruction). One mutation, c.775T>A (p.Y259N), recurred in six patients. Four cases derived from two small families; renal scars with urinary infection represented the main symptom at presentation in all but two patients. Transfection studies indicated a 5-10-fold increase in the levels of the mutant protein relative to wild-type SOX17 in transfected kidney cells. Moreover we observed a corresponding increase in the ability of SOX17 p.Y259N to inhibit Wnt/β-catenin transcriptional activity, which is known to regulate multiple stages of kidney and urinary tract development. In conclusion, SOX17 p.Y259N mutation is recurrent in patients with CAKUT. Our data shows that this mutation correlates with an inappropriate accumulation of SOX17-p.Y259N protein and inhibition of the β-catenin/Wnt signaling pathway. These data indicate a role of SOX17 in human kidney and urinary tract development and implicate the SOX17-p.Y259N mutation as a causative factor in CAKUT.

The tumor suppressor gene TRC8/RNF139 is disrupted by a constitutional balanced translocation t(8;22)(q24.13;q11.21) in a young girl with dysgerminoma

Background

RNF139/TRC8 is a potential tumor suppressor gene with similarity to PTCH, a tumor suppressor implicated in basal cell carcinomas and glioblastomas. TRC8 has the potential to act in a novel regulatory relationship linking the cholesterol/lipid biosynthetic pathway with cellular growth control and has been identified in families with hereditary renal (RCC) and thyroid cancers. Haploinsufficiency of TRC8 may facilitate development of clear cell-RCC in association with VHL mutations, and may increase risk for other tumor types. We report a paternally inherited balanced translocation t(8;22) in a proposita with dysgerminoma.

Methods

The translocation was characterized by FISH and the breakpoints cloned, sequenced, and compared. DNA isolated from normal and tumor cells was checked for abnormalities by array-CGH. Expression of genes TRC8 and TSN was tested both on dysgerminoma and in the proposita and her father.

Results

The breakpoints of the translocation are located within the LCR-B low copy repeat on chromosome 22q11.21, containing the palindromic AT-rich repeat (PATRR) involved in recurrent and non-recurrent translocations, and in an AT-rich sequence inside intron 1 of the TRC8 tumor-suppressor gene at 8q24.13. TRC8 was strongly underexpressed in the dysgerminoma. Translin is underexpressed in the dysgerminoma compared to normal ovary.

TRC8 is a target of Translin (TSN), a posttranscriptional regulator of genes transcribed by the transcription factor CREM-tau in postmeiotic male germ cells.

Conclusion

A role for TRC8 in dysgerminoma may relate to its interaction with Translin. We propose a model in which one copy of TRC8 is disrupted by a palindrome-mediated translocation followed by complete loss of expression through suppression, possibly mediated by miRNA.

SPECT and epilepsy with continuous spike waves during slow-wave sleep

Ten cases of epilepsy with continuous spike waves in slow-wave sleep (CSWS) were evaluated using single photon emission computed tomography (SPECT); in eight patients the EEG paroxysmal abnormalities showed a predominant localization. SPECT carried out using 99mTc-HMPAO allows study of cerebral blood flow (CBF); the examination was performed during phases of drowsiness and the results compared to the EEG data. In four cases SPECT revealed areas of low CBF in sites corresponding to those of the prevalent EEG discharges; in two cases the areas of hypoperfusion did not correspond to those indicated by the EEG; lastly, in four cases SPECT results were negative. The areas of hypoperfusion were predominantly located in the frontal, temporal, and parietal regions. Furthermore, the percentage of positive SPECT results was significantly higher (five cases out of six) in the group in which the CSWS phase was prolonged for at least 1 year, compared to the group in which this phase lasted less than 1 year. Thus, in this type of epilepsy, SPECT reveals focal cortical areas of decreased CBF which correlated generally to the predominant sites of EEG abnormalities. A longer duration of the CSWS phase seems to be associated with a more significant cortical disorder, documented by the presence of areas of hypoperfusion.

Comparative evaluation of SPECT, CT and CW Doppler data in patients with ischemic lesions of the brain

We report the SPECT, CT and CW Doppler findings in a series of 117 patients with cerebral ischemic lesions and correlate them with the clinical findings. SPECT-PAO proved to be more sensitive in localizing focal lesions than CT, which in 50% of the cases was normal or yielded an image of cerebral atrophy. In the latter cases CW Doppler ultrasound on the supraaortic trunks showed changes, circumscribed or diffuse. On the CW Doppler and SPECT evidence we consider that the CT image of cerebral atrophy may denote an alteration of the cerebral blood flow and metabolism and should be assessed in this light in the diagnosis and prognosis of cerebral ischemic lesions.

In-vitro activity of quinolones against different species of staphylococci of recent clinical isolation

We considered 256 strains of S. aureus (SA) and S. non-aureus (SnA) of recent clinical isolation. Their susceptibility (S) or resistance (R) to pefloxacin, ciprofloxacin, enoxacin, ofloxacin (which have been used in therapy for several years) and to timentin as well, has been tested, in relation with methicillin susceptibility (MS) and methicillin resistance (MR). To date, the activity of quinolones against all staphylococci remains relatively high, notwithstanding the appearance of resistant strains, in particular among MR SnA. Of the four quinolones examined, ofloxacin showed to be the most active, i.e. effective against 100% of the staphylococci, either SA or SnA.