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Biomedical subjects

M G Mattei

Publications and source records attributed to M G Mattei.

421 records · Page 24Linked to original sources
PubMedDate not supplied

Phenotype-genotype correlation in 20 deletion and 20 non-deletion Angelman syndrome patients.

Angelman syndrome (AS) is a neurodevelopmental disorder caused by the absence of a maternal contribution to chromosome 15q11-q13. There are four classes of AS according to molecular or cytogenetic status: maternal microdeletion of 15q11-q13 (approximately 70% of AS patients); uniparental disomy (UPD); defects in a putative imprinting centre (IM); the fourth includes 20-30% of AS individuals with biparental inheritance and a normal pattern of allelic methylation in 15q11-q13. Mutations of UBE3A have recently been identified as causing AS in the latter group. Few studies have investigated the phenotypic differences between these classes. We compared 20 non-deletion to 20 age-matched deletion patients and found significant phenotypic differences between the two groups. The more severe phenotype in the deletion group may suggest a contiguous gene syndrome.

Adolescent↗
PubMedDate not supplied

Trisomy 12p syndrome: a chromosomal disorder associated with generalized 3-Hz spike and wave discharges.

Three cases (2 boys, 1 girl) of trisomy 12p syndrome are reported. In two, the disorder is caused by a malsegregation of a maternal translocation, the karyotype being 46,XY,der(18),t(12;18)(p11;q23) (case 2) and 46,XX,-10,+ der(10),t(10;12)(p15;p11) (case 3). Case 1 is a de novo case with a regular trisomy 12p in the fibroblasts: 47,XY + (12pter----12 cen. . .?) and a mosaic trisomy 12p in lymphocytes: 46,XY/47,XY, + (12pter----12 cen. . .?). In all cases, the EEG showed 3-Hz generalized spike and wave (SW) discharges. Generalized epilepsy with myoclonic seizures was present in two patients (cases 1 and 2), who may be considered to have a symptomatic generalized epilepsy with a specific etiology. Case 3 has shown only febrile seizures. Any association between the excess of genetic material and the EEG trait "generalized SW" might not be a chance occurrence in this disorder; however, both EEG findings and clinical features (seizure type and frequency) in the 23 cases reported in the literature are too scanty to allow confirmation of such an association.

Brain↗
PubMedDate not supplied

[Contribution of in situ hybridization to chromosomal analysis].

In situ hybridization (ISH) is a new technique which allows localizing on chromosomes a molecule of DNA homologous to a given sequence of nucleic acids. It permits to improve the chromosomal analysis by marking any sequence of nucleic acids in interphase or metaphase. It opens new prospects for chromosomes mapping, study of evolution, chromosomal diagnosis, the role of oncogenes and chromosomal mechanics.

Biological Evolution↗
PubMedDate not supplied

[The evolution of epilepsy in the most common genetic forms with mental retardation (Down's syndrome and the fragile X syndrome)].

Some chromosomal abnormality syndromes carry a higher risk of seizures than that found in the general population. Down's syndrome is considered to be the first and the most frequent chromosomal abnormality causing mental retardation. In spite of numerous reports and epidemiological surveys, the outcome of epileptic syndromes in patients with Down's syndrome (DS) is still largely unknown. We retrospectively studied 34 DS patients with epilepsy (14M; 20F). Epileptic syndromes were classified as: infantile spasms, 10 cases, i.e. 31%; Lennox-Gastaut syndrome, 5 cases, 15.5%; symptomatic generalized epilepsy, 1 case; idiopathic generalized epilepsy, 6 cases, 17.6%; partial symptomatic epilepsy, 10 cases, i.e. 31%. In 2 patients the epilepsy was unclassifiable. In all the patients the following evolutive particularities were noted: a) the infantile spasms to have a relatively mild prognosis, as 8/10 patients remained seizure-free, 3 of whom without treatment; b) no patient experienced febrile convulsions prior to the onset of epilepsy; c) Lennox-Gastaut syndrome had a relatively late onset (mean age 10 years, range 8-11.5); d) 7 patients (20.6%) developed reflex seizure. The fragile X syndrome is considered to be the second most frequent chromosomal abnormality causing mental retardation. The prevalence of epilepsy varies from 9.1% to 45% in the different series. In order to evaluate the prevalence rate of epilepsy and the previously hypothesized association with a particular electroclinical picture, we retrospectively studied 90 fragile X syndrome patients (80M, 10F) aged 4 to 25 years (mean age 13y6m).(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMedDate not supplied

Chromosomal localization of the adrenoleukodystrophy-related gene in man and mice.

We report here on the chromosomal mapping of the adrenoleukodystrophy-related (ALDR) gene on both the human and the mouse genomes. This gene encodes a peroxisomal ATP binding cassette transporter, closely related to the transporter identified as responsible for the adrenoleukodystrophy phenotype. ALDR maps on the syntenic region on murine and human autosomes. In addition, we could determine its position in relation to known microsatellite framework markers; this will allow to test its role in Zellweger syndrome and/ or related peroxisomal disorders.

ATP Binding Cassette Transporter, Subfamily D↗
PubMedDate not supplied

The mouse Necdin gene is expressed from the paternal allele only and lies in the 7C region of the mouse chromosome 7, a region of conserved synteny to the human Prader-Willi syndrome region.

Prader-Willi syndrome (PWS) is a neurogenetic disorder resulting from the loss of paternal expression of gene(s) localized in the 15q11-q12 region. A new human gene encoding a putative protein with high homology to the mouse NECDIN protein has recently been characterized and mapped to chromosome 15q11-q12. It is expressed from the paternal allele only, suggesting its potential involvement in PWS. We now report the localization of the mouse Necdin gene in a region of conserved synteny to the human PWS region. We demonstrate the paternal specific expression of Necdin in the mouse central nervous system, and show that parental alleles display a differential methylation profile in the coding region. Finally, fluorescence in situ hybridization analysis reveals an asynchronous pattern of replication at the Necdin locus. These results clearly demonstrate imprinting of the mouse Necdin gene. Mouse models will be powerful tools in the study of human PWS phenotype and imprinting mechanisms.

Alleles↗