SOD1 p.D12Y variant is associated with amyotrophic lateral sclerosis/distal myopathy spectrum.

BACKGROUND AND PURPOSE: The aim of our study was to describe patients with the p.D12Y variant (previously reported as D11Y) in SOD1 showing heterogeneous clinicopathological features. METHODS: We performed clinical, electrophysiological, magnetic resonance imaging (MRI) and muscle pathology studies in four SOD1 p.D12Y variant-positive patients. RESULTS: The SOD1 p.D12Y clinical manifestations ranged from a benign phenotype characterized by distal distribution of muscular weakness and long survival to classic forms of amyotrophic lateral sclerosis with poor prognosis. Two patients with the distal clinical phenotype showed MRI and muscle pathology alterations indicating a concurrent muscle involvement. In one of these patients significant myopathic changes were associated with rimmed vacuolar pathology. CONCLUSIONS: We expand the clinical spectrum of SOD1 p.D12Y variant, including predominant lower motor neuron forms with long survival and classic forms with aggressive course. Some patients may have concomitant distal myopathy without other explanations. Given clinical, MRI and muscle pathology alterations, SOD1 should be considered in the differential diagnosis of molecularly undefined distal myopathies with rimmed vacuoles.

Germinal mosaicism for a deletion of the FMR1 gene leading to fragile X syndrome.

Aberrant CGG trinucleotide amplification within the FMR1 gene, which spans approximately 38 Kb of genomic DNA is almost always what leads to fragile X syndrome (FXS). However, deletions of part or the entire FMR1 gene can also cause FXS. Both CGG amplification-induced silencing and deletions result in the absence of the FMR1 gene product, FMRP. Here, we report a rare case of germinal mosaicism of a deletion encompassing approximately 300 Kb of DNA, which by removing the entire FMR1 gene led to FXS. The male proband, carrying the deletion, presented in clinic with the typical features of FXS. His mother was analyzed by FISH on metaphase chromosomes with cosmid probe c22.3 spanning the FMR1 locus, and she was found not to carry the deletion on 30 analyzed cells from peripheral blood lymphocytes. Prenatal examination of the mother's third pregnancy showed that the male fetus also had the same deletion as the proband. Following this prenatal diagnosis, FISH analysis in the mother was expanded to 400 metaphases from peripheral lymphocytes, and a heterozygous FMR1 deletion was found in three. Although this result could be considered questionable from a diagnostic point of view, it indicates that the deletion is in the ovary's germinal cells.

Clinical and genetic heterogeneity of amyotrophic lateral sclerosis.

Although clinical picture of amyotrophic lateral sclerosis (ALS) is a stereotypical one, resulting from combination of signs secondary to dysfunction of both upper motor neuron (UMN) and lower motor neuron (LMN), clinical heterogeneity is a consistent feature of the disease. Age of onset, relative mix of UMN and LMN signs, duration of the disease and association with other conditions are major factors contributing to variable clinical phenotypes. Genetically, familial forms of ALS are associated with a large number of pleiotropic genes whose mutations impair different biochemical pathways, resulting in overlapping clinical and pathological phenotypes. Over the last few years contribution of large- and low-effect genes to sporadic ALS is increasingly recognized.

D11Y SOD1 mutation and benign ALS: a consistent genotype-phenotype correlation.

We describe three sporadic ALS patients in which a D11Y SOD1 mutation was detected. All three patients disclosed a prolonged survival and a stereotypical distal limbs involvement in the initial stages of the disease. By this report we demonstrate that D11Y SOD1 mutation is associated with a peculiar phenotype and we confirm its probable pathogenetic role.

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], approximately 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.

Natural history of young-adult amyotrophic lateral sclerosis.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) affects people of all ages, but whether the wide range of age at onset is due to distinct diseases or merely reflects phenotypic variability of the same disorder is still unknown. The purpose of this study is to describe clinical and prognostic features of young-adult ALS, with onset before age 40 years, and to compare them with features of the common adult-onset type. METHODS: We analyzed clinical features and long-term follow-up of 57 young-adult ALS patients, with disease onset between 20 and 40 years, and compared them with 450 patients affected by adult-onset ALS. RESULTS: We found that the majority of young-adult patients showed a predominant upper motor neuron (p-UMN) ALS, characterized by marked spastic paraparesis, with lower motor neuron signs confined to the upper limbs. The proportion of patients with p-UMN ALS phenotype was 59.6% in the young-adult patients and 17.4% in the adult-onset form (p < 0.0001). Young-adult ALS with p-UMN phenotype had longer survival than did the classic phenotype: median survival was 74 months (range 10-226, 95% CI 60.61-87.38) in the former and 56 months (range 6-106, 95% CI 48.65-63.34) in the latter (p = 0.03). In the young-adult patients, a marked male excess was observed in the p-UMN ALS group (5.8:1), whereas the ratio of men to women was 1.1:1 in the classic phenotype (p = 0.01). CONCLUSIONS: Our findings show that young-adult amyotrophic lateral sclerosis with the predominant upper motor neuron phenotype represents a distinctive clinical variant characterized by a unique clinical pattern, longer survival, and male prevalence.

Clinical and molecular characteristics of 1qter microdeletion syndrome: delineating a critical region for corpus callosum agenesis/hypogenesis.

BACKGROUND: Patients with a microscopically visible deletion of the distal part of the long arm of chromosome 1 have a recognisable phenotype, including mental retardation, microcephaly, growth retardation, a distinct facial appearance and various midline defects including corpus callosum abnormalities, cardiac, gastro-oesophageal and urogenital defects, as well as various central nervous system anomalies. Patients with a submicroscopic, subtelomeric 1qter deletion have a similar phenotype, suggesting that the main phenotype of these patients is caused by haploinsufficiency of genes in this region. OBJECTIVE: To describe the clinical presentation of 13 new patients with a submicroscopic deletion of 1q43q44, of which nine were interstitial, and to report on the molecular characterisation of the deletion size. RESULTS AND CONCLUSIONS: The clinical presentation of these patients has clear similarities with previously reported cases with a terminal 1q deletion. Corpus callosum abnormalities were present in 10 of our patients. The AKT3 gene has been reported as an important candidate gene causing this abnormality. However, through detailed molecular analysis of the deletion sizes in our patient cohort, we were able to delineate the critical region for corpus callosum abnormalities to a 360 kb genomic segment which contains four possible candidate genes, but excluding the AKT3 gene.

Megalencephaly and perisylvian polymicrogyria with postaxial polydactyly and hydrocephalus (MPPH): report of a new case.

Megalencephaly (MEG), or enlargement of the brain, can either represent a familial variant with normal cerebral structure, or a rare brain malformation associated with developmental delay and neurological problems. MEG has been split into two subtypes: anatomical and metabolic. The latter features a build-up inside the cells owing to metabolic causes. Anatomical MEG has been detected in many different conditions, including many overgrowth syndromes. In 2004 Mirzaa et al. reported five non-consanguineous patients with a new MCA/MR syndrome characterized by severe congenital MEG with polymicrogyria (PMG), postaxial polydactyly (POLY) and hydrocephalus (HYD). The authors argued that these findings identified a new and distinct malformation syndrome, which they named MPPH. We report on a new case of MPPH, the first to be described after the original series (Mirzaa et al., 2004).

Cryptic deletions are a common finding in "balanced" reciprocal and complex chromosome rearrangements: a study of 59 patients.

Using array comparative genome hybridisation (CGH) 41 de novo reciprocal translocations and 18 de novo complex chromosome rearrangements (CCRs) were screened. All cases had been interpreted as "balanced" by conventional cytogenetics. In all, 27 cases of reciprocal translocations were detected in patients with an abnormal phenotype, and after array CGH analysis, 11 were found to be unbalanced. Thus 40% (11 of 27) of patients with a "chromosomal phenotype" and an apparently balanced translocation were in fact unbalanced, and 18% (5 of 27) of the reciprocal translocations were instead complex rearrangements with >3 breakpoints. Fourteen fetuses with de novo, apparently balanced translocations, all but two with normal ultrasound findings, were also analysed and all were found to be normal using array CGH. Thirteen CCRs were detected in patients with abnormal phenotypes, two in women who had experienced repeated spontaneous abortions and three in fetuses. Sixteen patients were found to have unbalanced mutations, with up to 4 deletions. These results suggest that genome-wide array CGH may be advisable in all carriers of "balanced" CCRs. The parental origin of the deletions was investigated in 5 reciprocal translocations and 11 CCRs; all were found to be paternal. Using customized platforms in seven cases of CCRs, the deletion breakpoints were narrowed down to regions of a few hundred base pairs in length. No susceptibility motifs were associated with the imbalances. These results show that the phenotypic abnormalities of apparently balanced de novo CCRs are mainly due to cryptic deletions and that spermatogenesis is more prone to generate multiple chaotic chromosome imbalances and reciprocal translocations than oogenesis.

Brain magnetic resonance imaging in Wolf-Hirschhorn syndrome.

Wolf-Hirschhorn syndrome (WHS) is a rare genetic disorder, which is caused by partial deletion of the short arm of one chromosome 4. Brain magnetic resonance (MR) imaging findings are lacking. We report on brain findings in 10 children with WHS. We evaluated the MR imaging films of 10 subjects affected by WHS, which had been confirmed by genetic study. The age range at MR imaging was between 1 month and 9 years. In 9/10 cases enlargement of the third lateral ventricles was present. In 9/10 cases a global reduction of cerebral hemispheres white matter was present. In 10/10 cases diffuse thinning of the corpus callosum was visible; it was severe in 7/10 cases. In 5/10 cases small foci of T (2) hyper intense signal were visible within the subcortical white matter. In three of the six cases studied within the first year of life frontal periventricular cysts were present. In three of the four cases studied after the first year of life a squared shape of the frontal horns of the lateral ventricles was visible. The MR imaging findings reported in WHS cannot be considered pathognomonic of the syndrome, however, they may suggest WHS.

The first 4p euchromatic variant in a healthy carrier having an unusual reproductive history.

We report on the molecular cytogenetics studies in a healthy couple who had had three pregnancies which ended in a termination of pregnancy (TOP). In two of them, prenatal sonogram showed fetal dwarfism and in the third one, a chromosome alteration was found in the amniocentesis. A previous pregnancy ended in a healthy girl. A high-resolution G-band karyotype (550-850 bands), together with Fluorescence in situ Hybridization (FISH) techniques, detected in the father a 4p interstitial euchromatic duplication. This chromosome duplication appears to be a previously undescribed euchromatic variant (EV). We discuss the possibility that the 4p paternal EV could be involved in the clinical and genetic findings of the three TOPs.

Reduced BRCA1 expression due to promoter hypermethylation in therapy-related acute myeloid leukaemia.

BRCA1 plays a pivotal role in the repair of DNA damage, especially following chemotherapy and ionising radiation. We were interested in the regulation of BRCA1 expression in acute myeloid leukaemia (AML), in particular in therapy-related forms (t-AML). Using real-time PCR and Western blot, we found that BRCA1 mRNA was expressed at barely detectable levels by normal peripheral blood granulocytes, monocytes and lymphocytes, whereas control BM-mononuclear cells and selected CD34+ progenitor cells displayed significantly higher BRCA1 expression (P=0.0003). Acute myeloid leukaemia samples showed heterogeneous BRCA1 mRNA levels, which were lower than those of normal bone marrows (P=0.0001). We found a high frequency of hypermethylation of the BRCA1 promoter region in AML (51/133 samples, 38%), in particular in patients with karyotypic aberrations (P=0.026), and in t-AML, as compared to de novo AML (76 vs 31%, P=0.0002). Examining eight primary tumour samples from hypermethylated t-AML patients, BRCA1 was hypermethylated in three of four breast cancer samples, whereas it was unmethylated in the other four tumours. BRCA1 hypermethylation correlated to reduced BRCA1 mRNA (P=0.0004), and to increased DNA methyltransferase DNMT3A (P=0.003) expression. Our data show that reduced BRCA1 expression owing to promoter hypermethylation is frequent in t-AML and that this could contribute to secondary leukaemogenesis.

Genitourinary anomalies in Mowat-Wilson syndrome with deletion/mutation in the zinc finger homeo box 1B gene (ZFHX1B). Report of three Italian cases with hypospadias and review.

Hypospadias, when the urethra opens on the ventral side of the penis, is a common malformation seen in about 3 per 1,000 male births. It is a complex disorder associated with genetic and environmental factors and can be part of genetic syndromes. Mowat-Wilson syndrome (MWS) is a multiple congenital anomaly syndrome characterized by a distinct facial phenotype, Hirschsprung disease, microcephaly and mental retardation. It is caused by mutations in the zinc finger homeo box 1B gene, ZFHX1B (SIP1). To date, 68 deletion/mutation-positive cases have been reported. Genitourinary anomalies are common in MWS. Here we report that hypospadias is common in males with this syndrome. In 39 patients where this information was available, hypospadias was present in 46% of patients (18/39). In the 3 Italian male cases reported here, hypospadias was always present. MWS should be considered by endocrinologists in patients with hypospadias associated with developmental delays/mental retardation, in particular in the presence of a distinct facial phenotype.

A novel microdeletion syndrome with loss of the MSH2 locus and hereditary non-polyposis colorectal cancer.

Constitutional chromosome deletions can predispose to the development of cancer with the phenotypic characteristics of inherited cancer syndromes, when the deleted region encompasses a tumour suppressor gene. Examples of such conditions are represented by the cytogenetic deletions associated with retinoblastoma, Wilms tumour and familial adenomatous polyposis. So far, no constitutional deletions involving the genes implicated in hereditary non-polyposis colorectal cancer (HNPCC) have been identified. This may be at least partially because of the lack of distinctive phenotypic manifestations in HNPCC. We describe the first case of a constitutional microdeletion associated with HNPCC. Suspicion of a microdeletion was prompted by the association of mental retardation, postnatal growth deficiency, minor congenital anomalies and early onset (37 years) sporadic colon cancer. The patient was found to harbour a microdeletion within chromosome 2p16-p21, including the MSH2 gene. Since there are very few reports of deletions of the 2p16-p21 region, our observation sets the grounds for the definition of a novel multiple congenital anomaly/mental retardation/cancer microdeletion syndrome.

Early-onset encephalopathy and cortical myoclonus in a boy with MECP2 gene mutation.

The authors report the unusual clinical and neurophysiologic features of a sporadic case of a boy carrying an 806delG mutation on the MECP2 gene. A 28-month-old boy was examined for severe developmental delay, seizures, microcephaly, breathing dysfunction, and spontaneous and evoked myoclonic jerks of upper limbs. Neurophysiologic study proved the cortical origin of myoclonus; however, it was not associated with signs of cortical hyperexcitability. 3-Methoxy-4-hydroxy-phenylethylene glycol and valine concentrations were low in CSF.

Assisted reproductive technology and congenital overgrowth: some speculations on a case of Pallister-Killian syndrome.

We report on a boy with Pallister-Killian syndrome (PKS) who was conceived by assisted reproductive technology (ART), specifically in vitro fertilization (IVF) with parents' gametes. A prenatal diagnosis performed elsewhere by CVS failed to detect the presence of the isochromosome 12p that was demonstrated postnatally in approximately 50% of cultured skin fibroblasts. Given that the patient did not show the congenital overgrowth typical of PKS, we speculate that ART might have restricted overgrowth in this particular case. More broadly, we hypothesize that overgrowth might protect from early demise fetuses conceived by ART, a technology known to cause low and very low birth weight.

Absence of 12q21.2q22 deletions and subtelomeric rearrangements in cardiofaciocutaneous (CFC) syndrome patients.

Recent publications described two patients with a CFC-like phenotype and the same deletion of chromosome region 12q21.2q22 [Rauen et al., 2000, 2002]. The patients did not have the classical CFC phenotype and presented other signs not usually seen in CFC patients: the first patient had hydrocephalus, and the second, a history of olygohydramnios, normal stature, pyloric stenosis, cutaneous syndactyly of toes and bilateral transverse palmar creases. In order to verify if classic CFC patients with normal chromosomes in conventional preparations have microdeletions within the 12q21.2q22 chromosome region, we performed FISH analysis using 12 BAC probes to screen this area. The average interval between the probes was of approximately 1 Mb. No deletions were found in any of the 17 classical CFC patients we examined. We conclude that the region 12q21.2q22 is not a candidate region for CFC syndrome and that the patients described by Rauen et al. [2000, 2002] probably have a different condition, i.e., an aneuploidy syndrome, with some phenotypic resemblance to the CFC syndrome. To further evaluate the possibility of other chromosome imbalances, we performed a subtelomeric analysis, by FISH technique, of all chromosomes, and did not find any subtelomeric rearrangements.

PTPN11 mutations are not responsible for the Cardiofaciocutaneous (CFC) syndrome.

Cardiofaciocutaneous (CFC) syndrome is a multiple congenital anomalies/mental retardation syndrome characterized by congenital heart defects, characteristic facial appearance, short stature, ectodermal abnormalities and mental retardation. It was described in 1986, and to date is of unknown genetic etiology. All reported cases are sporadic, born to non-consanguineous parents and have apparently normal chromosomes. Noonan and Costello syndromes remain its main differential diagnosis. The recent finding of PTPN11 missense mutations in 45-50% of the Noonan patients studied with penetrance of almost 100% and the fact that in animals mutations of this gene cause defects of semilunar valvulogenesis, made PTPN11 mutation screening in CFC patients a matter of interest. We sequenced the entire coding region of the PTPN11 gene in ten well-characterised CFC patients and found no base changes. We also studied PTPN11 cDNA in our patients and demonstrated that there are no interstitial deletions either. The genetic cause of CFC syndrome remains unknown, and PTPN11 can be reasonably excluded as a candidate gene for the CFC syndrome, which we regard as molecular evidence that CFC and Noonan syndromes are distinct genetic entities.