Preimplantation Genetic Testing for Spastic Paraplegia Type 3

INTRODUCTION

Spastic paraplegia type 3 (SPG3) is a common autosomal dominant neurogenetic disease, presenting during childhood with symptoms of mildly progressive spasticity and weakness of the lower limbs. SPG3 develops due to mutations of the ATL1 gene that encodes atlastin-1, a GTPase crucial for the function of dendrites of corticospinal neurons. Here we present a case of preimplantation genetic testing for SPG3.

PATIENT AND METHODS

A 30-year-old woman with clinical symptoms of autosomal dominant spastic paraplegia since her first year of life asked for genetic counselling. DNA sequencing revealed the existence of mutation c.715C>T (p. R239C) in the ATL1 gene, confirming the diagnosis of SPG3. The patient asked for preimplantation testing for SPG3 after in vitro fertilization. An allele-specific method of PCR amplification was created in order to distinguish the mutant and the normal allele in the patient and her mother who also had SPG3, while her normal father served as control. The same nested PCR approach was used for the preimplantation testing of 11 available embryos.

RESULTS

The presence of the c.715C>T (p. R239C) mutation in the ATL1 gene was found in five embryos while six embryos carried normal alleles and were selected for IVF implantation. After three failed gestation attempts and one pregnancy ended by a spontaneous miscarriage in the first trimester due to a chromosomal abnormality, there was an achieved pregnancy with a totally normal embryo.

CONCLUSION

SPG3 may be degrading to a patient's quality of life; therefore, appropriate genetic counselling and preimplantation molecular testing may be provided as an option of prevention in offspring.

Mutation Screening of Her-2, N-ras and Nf1 Genes in Brain Tumor Biopsies

BACKGROUND/AIM

A deeper understanding of the complex molecular pathology of brain malignancies is needed in order to develop more effective and targeted therapies of these highly lethal disorders. In an effort to further enlighten the molecular pathology of brain oncogenesis involving the her-2 (erbB-2/neu/ngl)/N-ras/nf1 pathway, we screened the genotypes of specimens from various types of brain tumors.

MATERIALS AND METHODS

The studied specimens included 35 biopsies of four general categories: 13 neuroglial tumors (4 astrocytomas, 2 oligodendrogliomas, 7 glioblastomas multiforme), 14 meningiomas, 3 other nervous system tumors (2 schwannomas, 1 craniopharyngioma) and 5 metastatic tumors (such as lung carcinomas and chronic myelocytic leukemia). Screening for most common mutations in oncogenes her-2, N-ras and tumor suppressor gene nf1 was conducted with molecular hybridization techniques (Southern blotting, dot blot and single-strand conformational polymorphism (SSCP) analysis, respectively), and was confirmed by DNA sequencing.

RESULTS

Gene amplification of her-2 was observed in only two cases (6%), namely in one glioblastoma and in one meningioma. Screening of 3 hot spot codons of the N-ras gene (12, 13 and 61) and subsequent DNA sequencing revealed mutations in 19 biopsies encompassing all categories (54%). Screening for mutations in exons of the nf1 gene by SSCP analysis detected a novel nonsense mutation in exon 31 in a unique case of a glioblastoma biopsy (3%) taken from a patient without neurofibromatosis type I.

CONCLUSION

Activated N-ras appears to be a major oncogene in brain oncogenesis, exhibiting the most important role in the her-2/N-ras/nf1 pathway.

Neurofibromatosis-Noonan Syndrome: A Possible Paradigm of the Combination of Genetic and Epigenetic Factors

Neurofibromatosis-Noonan syndrome (NFNS) is a clinical entity possessing traits of autosomal dominant disorders neurofibromatosis type 1 (NF1) and Noonan syndrome (NS). Germline mutations that disrupt the RAS/MAPK pathway are involved in the pathogenesis of both NS and NF1. In light of a studied Greek family, a new theory for etiological pathogenesis of NFNS is suggested. The NFNS phenotype may be the final result of a combination of a genetic factor (a mutation in the NF1 gene) and an environmental factor with the epigenetic effects of muscle hypotonia (such as hydantoin in the reported Greek family), causing hypoplasia of the face and micrognathia.

Is Neurofibromatosis Type 1-Noonan Syndrome a Phenotypic Result of Combined Genetic and Epigenetic Factors?

BACKGROUND/AIM

Neurofibromatosis 1-Noonan syndrome (NFNS) presents combined characteristics of both autosomal dominant disorders: NF1 and Noonan syndrome (NS). The genes causing NF1 and NS are located on different chromosomes, making it uncertain whether NFNS is a separate entity as previously suggested, or rather a clinical variation.

PATIENTS AND METHODS

We present a four-membered Greek family. The father was diagnosed with familial NF1 and the mother with generalized epilepsy, being under hydantoin treatment since the age of 18 years. Their two male children exhibited NFNS characteristics.

RESULTS

The father and his sons shared R1947X mutation in the NF1 gene. The two children with NFNS phenotype presented with NF1 signs inherited from their father and fetal hydantoin syndrome-like phenotype due to exposure to that anticonvulsant during fetal development.

CONCLUSION

The NFNS phenotype may be the result of both a genetic factor (mutation in the NF1 gene) and an epigenetic/environmental factor (e.g. hydantoin).

Potential prevention of thromboembolism by genetic counseling and testing for two common thrombophilia mutations

BACKGROUND/AIM

Thrombophilia is a multifactorial predisposition for thromboembolism affecting about a tenth of any population. We investigated whether genetic counseling combined with molecular testing for two common dominant mutations (coagulation factor V Leiden and prothrombin G20210A) may increase prevention of venous thromboembolic incidents in individuals with a positive family history compared to the general population.

PATIENTS AND METHODS

Mutation detection was carried out by Restriction Fragment Length Polymorphism analysis in DNA samples of 96 unrelated healthy Greeks (group A) who asked for genetic counseling for various reasons and had at least two relatives with thromboembolic incidents and 100 unrelated healthy Greeks (group B).

RESULTS

In group A, both mutations were detected at five-fold higher frequencies (33.33% for Leiden and 19.79% for G20210A) compared to group B, which had frequencies typically found in the Greek population (6% and 4%, respectively).

CONCLUSION

In populations with a high prevalence for these two common mutations, genetic counseling and molecular testing of at-risk individuals may significantly increase prevention of thromboembolic disease.

Emotional and behavioural difficulties in children of parents with multiple sclerosis: a controlled study in Greece

Emotional and behavioural problems were investigated in children who have a parent with multiple sclerosis (MS), in relation to factors such as family dysfunction, parental depression and illness-related characteristics. The participants were 56 MS patients, their spouses and one randomly selected child aged 4-17 years, and a comparison group of 64 children and both their parents, none of whom reported somatic illness. Emotional and behavioural problems in the children were identified by reporting of both parents and self-report using the Achenbach's Child Behaviour Checklist and Youth Self Report respectively. Parental depression and family dysfunction were explored using the Beck Depression Inventory and Family Assessment Device, respectively. The data were analysed using independent samples t-tests for between-group comparisons, Pearson r correlations between children's problems and family dysfunction or parental depression, and multiple regression analyses for identifying predictors for children's problems. Children whose parents, especially mothers, had MS presented greater emotional and behavioural problems than comparison children. Children's problems were positively associated with maternal depression and family dysfunction. Family dysfunction predicted children's overall and externalizing problems, while the severity of impairment of the ill mother predicted children's internalizing problems. Implications of these findings for clinical practice are discussed.

Brain MR post-gadolinium contrast in multiple sclerosis: the role of magnetization transfer and image subtraction in detecting more enhancing lesions

Our purpose was to evaluate the role of magnetization transfer and image subtraction in detecting more enhancing lesions in brain MR imaging of patients with multiple sclerosis (MS). Thirty-one MS patients underwent MR imaging of the brain with T1-weighted spin echo sequences without and with magnetization transfer (MT) using a 1.5 T imager. Both sequences were acquired before and after intravenous injection of a paramagnetic contrast agent. Subtraction images in T1-weighted sequences were obtained by subtracting the pre-contrast images from the post-contrast ones. A significant difference was found between the numbers of enhanced areas in post-gadolinium T1-weighted images without and with MT (p=0.020). The post-gadolinium T1-weighted images with MT allowed the detection of an increased (13) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. A significant difference was also found between the numbers of enhanced areas in post-gadolinium T1-weighted images without MT and subtraction images without MT (p=0.020). The subtraction images without MT allowed the detection of an increased (10) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. Magnetization transfer contrast and subtraction techniques appear to be the simplest and least time-consuming applications to improve the conspicuity and detection of contrast-enhancing lesions in patients with MS.

Serum anti-GM1 and anti-GD1a antibodies in patients with motor neuron disease

Using an enzyme-linked immunosorbent assay (ELISA) sera from 100 individuals, 20 with motor neuron disease (MND), 25 with peripheral neuropathy (PN), 15 with degenerative dementia and 40 controls, were examined in order to detect serum IgM and IgG anti-GM1 and anti-GD1a antibodies. Patients with MND showed statistically significant higher levels of IgM anti-GM1 antibody compared to the control group. Three patients with peripheral neuropathy had very high levels of anti-GM1 and anti-GD1a antibodies. Antibody levels in patients with degenerative dementia showed no difference compared to the controls. These results suggest that a further inquiry into the role of serum anti-GM1 and anti-GD1a activity in motor neuron disease and peripheral neuropathy is necessary.

Amyotrophic lateral sclerosis in southern Greece: an epidemiologic study

All amyotrophic lateral sclerosis cases hospitalized over a 25-year period in the University Department of Neurology in Athens were surveyed, with emphasis given to the occupation of the patients and the geographic distribution of the disease. The results showed an overrepresentation of farmers among patients and an aggregation of cases in the region of Cephalonia. These findings might suggest that environmental factors could be involved in the etiology of the disease.