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Biomedical subjects

M Lerone

Publications and source records attributed to M Lerone.

At least 55 records · Page 3Linked to original sources
PubMed1994

Heterogeneity and low detection rate of RET mutations in Hirschsprung disease.

Mutations in some exons of the RET proto-oncogene were recently observed in Hirschsprung patients. Using DNA polymorphisms and single-strand conformation polymorphism analysis for the whole coding sequence of the RET proto-oncogene, 82 unrelated Hirschsprung patients were screened systematically. A total of 4 complete deletions of RET and 12 point mutations were identified, each present in no more than one patient and distributed along the whole gene. De novo mutations could be documented in 4 patients. Southern blot and fluorescence in situ hybridization analysis carried out in a restricted number of patients did not reveal any deletion of RET. The low efficiency in detecting mutations of RET in Hirschsprung patients (20%) may originate mainly from genetic heterogeneity.

Blotting, Southern↗
PubMed1993

Uncombable hair, retinal pigmentary dystrophy, dental anomalies, and brachydactyly: report of a new patient with additional findings.

A new ectodermal dysplasia syndrome was reported by Bork et al. in 1987 (Hautarzt 38:342-347). The syndrome consisted of hypotrichosis with the typical SEM (scanning electron microscopy) changes of uncombable hair, retinal pigmentary dystrophy, juvenile cataract, oligodontia, brachydactyly with brachymetacarpia; it was inherited as an autosomal dominant trait. We describe a sporadic case and add further clinical findings to expand the spectrum of this rare syndrome.

Bone and Bones↗
PubMed1993

A gene for Hirschsprung disease maps to the proximal long arm of chromosome 10.

Hirschsprung disease (HSCR) is a frequent congenital disorder (1 in 5,000 newborns) of unknown origin characterized by the absence of parasympathetic intrinsic ganglion cells of the hindgut. Taking advantage of a proximal deletion of chromosome 10q (del 10q11.2-q21.2) in a patient with total colonic aganglionosis, and of a high-density genetic map of microsatellite DNA markers, we performed genetic linkage analysis in 15 non-syndromic long-segment and short-segment HSCR families. Multipoint linkage analysis indicated that the most likely location for a HSCR locus is between loci D10S208 and D10S196, suggesting that a dominant gene for HSCR maps to 10q11.2, a region to which other neural crest defects have been mapped.

Base Sequence↗
PubMed1993

ICF syndrome with variable expression in sibs.

We describe a new familial case of ICF syndrome (immunodeficiency, centromeric instability, facial anomalies) in a woman of 29 years and in her brother of 30 years. The proband showed mental retardation, facial anomalies, recurrent respiratory infections, combined deficit of IgM and IgE immunoglobulin classes, and paracentromeric heterochromatin instability of chromosomes 1, 9, and 16. The brother had minor signs of the syndrome and had an apparently normal phenotype. Their parents were healthy and non-consanguineous. Chromosome anomalies consisted of homologous and non-homologous associations, chromatid and isochromatid breaks, deletions of whole arms, interchanges in the paracentromeric region, and multibranched configurations of chromosomes 1, 9, and 16. CD bands and fluorescence in situ hybridisation with alphoid DNA sequence probes specific for the centromeres of chromosomes 1 and 16 showed that the centromere was not directly implicated in the formation of multibranched configurations. These cases indicate the autosomal recessive mode of inheritance and the variable expressivity of the ICF syndrome.

Adult↗
PubMed1993

Deleted and normal chromosome 10 homologs from a patient with Hirschsprung disease isolated in two cell hybrids through enrichment by immunomagnetic selection.

A cytogenetically detectable deletion, del(10) (q11.2-->q21.2), was observed in a patient with total colonic aganglionosis with small bowel involvement (TCSA), a variant of Hirschsprung disease (HSCR). A similar deletion is present in another TCSA patient (S.M. Huson, personal communication). To reveal cytogenetically undetectable deletions of chromosome 10 in further patients, we developed a strategy for mapping chromosome 10 DNA markers with respect to the observed deletions. To this end, the two chromosome 10 homologs (deleted and normal) were segregated in two distinct somatic cell hybrids obtained after fusion of the patient's fibroblasts with a Chinese hamster ovary cell line (YH21). Hybrid cells containing chromosome 10 were selected for the expression of the gene coding for the beta subunit of the fibronectin receptor (FNRB), which maps to 10p11.2, using a monoclonal antibody against FNRB. Hybrid 185.O contains the deleted chromosome, whereas hybrid 179.Q contains the nondeleted one. Southern blot and PCR analysis of DNA from these two hybrids mapped the markers RBP3H4, RET, D10S15, D10S5, D10S22, and D10S88 inside the deletion and D10S170, CDC2, EGR2, and D10S19 outside the deletion. MEN2A and MEN2B have recently been mapped within the centromeric region closely linked to RBP3 and D10S15 (which are located inside the deletion) and cosegregate with HSCR in at least two different pedigrees. Since HSCR, MEN2A, and MEN2B represent defects of neural crest cell development, we hypothesize that they originate from mutations in different genes clustered in the centromeric region of 10q.

Animals↗
PubMed1992

Congenital diaphragmatic hernia associated with ipsilateral upper limb reduction defects: report of a case with thumb hypoplasia.

Four unrelated cases of congenital diaphragmatic hernia associated with ipsilateral upper limb reduction defects were reported by McCredie and Reid in 1978 (J Pediatr 92: 762-765). As contiguous segments of the cervical neural crest are involved in the development of diaphragm and arms, the authors suggested that an early injury to the cervical neural crest might be the common underlying pathogenesis. We describe here a further example of this malformation complex: a newborn with a left posterolateral diaphragmatic hernia associated with ipsilateral thumb hypoplasia.

Abnormalities, Multiple↗
PubMed1992

Autosomal recessive microcephaly with early onset seizures and spasticity.

We describe two siblings, a male and a female pair, born of consanguineous parents, affected with a rare genetic form of congenital microcephaly. The clinical syndrome is characterized by early onset myoclonic seizures, spasticity, and profound psychomotor retardation without detectable brain malformations. To date, only two kindreds and one sporadic case with a similar clinical picture have been observed and reported (Tolmie et al. 1987, Bundey & Griffiths 1977). The severity of the neurological features and their perinatal onset differentiate the syndrome from the more common autosomal recessive microcephaly with spasticity/seizures.

Child, Preschool↗
PubMed1992

Oculocerebral syndrome with hypopigmentation (Cross syndrome): report of a new case.

A syndrome of ocular and cutaneous hypopigmentation, severe mental retardation with spastic tetraplegia and athetosis was first observed by Cross in three siblings of an inbred Amish family. Since then, seven other patients, three sporadic and four with familial recurrence, have been reported in the literature, confirming the autosomal recessive inheritance. The clinical spectrum of the syndrome has been expanded to include true developmental defects of the CNS such as cystic malformation of the posterior fossa of the Dandy-Walker type. We report a new case of Cross syndrome.

Brain↗
PubMed1991

Genotype-phenotype correlation and germline mosaicism in DMD/BMD patients with deletions of the dystrophin gene.

The molecular analysis of 127 DMD/BMD patients showed that 73 of them (57%) had deletions in the dystrophin gene. Two different methods were used in this study: (a) hybridization of HindIII-digested genomic DNA with nine cDNA probes corresponding to the entire 14kb cDNA of the DMD gene; and (b) simultaneous amplification of nine exons of the DMD gene (multiplex DNA amplification) by the polymerase chain reaction (PCR). When the deletion breakpoints of the intragenic deletions were analyzed with regard to their phenotypic consequences, nine patients were found to represent exceptions to the reading-frame hypothesis. Information regarding mental development was also available for 61 of the 73 deleted patients and for 34 of the 54 non-deleted ones. The proportion of mentally retarded patients was found to be similar in the two groups (deleted, 15%; non-deleted, 18%). Finally, in one family, a junction fragment present in the patient was not found in the peripheral blood DNA of the mother but was present in the sister, thus indicating germline mosaicism in the mother.

Adolescent↗
PubMed1991

Rett syndrome: exclusion mapping following the hypothesis of germinal mosaicism for new X-linked mutations.

The hypothesis of germinal mosaicism in the unaffected mother of two half-sisters affected with Rett syndrome is postulated to explain the unusual recurrence of this genetic disorder affecting only females (1/10,000); it might be caused by new X-linked mutations with lethality in male fetuses. The analysis of 34 X-linked restriction fragment length polymorphisms (RFLPs) in these two affected females and in their unaffected mother and half-brother, together with the reconstruction of phase for 15 informative RFLPs in somatic cell hybrids retaining a single X chromosome from each female, has made it possible to exclude some regions of the X chromosome as possible sites of the mutation(s) causing Rett syndrome.

Cell Line↗
PubMed1991

Leiomyomatosis of oesophagus, congenital cataracts and hematuria. Report of a case with rectal involvement.

Isolated oesophageal leiomyomatosis in children is very rare. The association between leiomyomatosis of oesophagus and female genital tract and an Alport like hematuric nephritis has been recognized as a distinct entity by Garcia-Torres and Guarner. Since then few other cases of this syndrome have been observed. Congenital cataracts and neurosensory deafness have been added to the clinical spectrum. Autosomal dominant inheritance is suggested by the familial cases. We report a patient who presents, as a new finding, leiomyomatosis of the rectum.

Cataract↗
PubMed1990

A new syndrome with cerebro-oculo-skeletal-renal involvement.

We report on an infant male who presented with microcephaly of prenatal onset, schizencephaly, decorticated disturbance of the neurological function, congenital optic atrophy, abnormal eye movements and nystagmus. In addition, he had a skeletal dysplasia with predominant acromelic involvement and a renal disease characterized by both nephritic and nephrotic changes. The natural history of his condition included severe postnatal failure to thrive, lack of development of psychomotor milestones, intractable seizures, terminal renal insufficiency with early death. Such spectrum of phenotypic abnormalities has never been reported before and we suggest that it may represent a new syndromic entity. The differential diagnosis with the oculo-skeletal-renal syndromes, with the osteodysplastic primordial dwarfism of the Taybi-Linder type and with the Hutterite cerebro-osteo-nephrodysplasia, is discussed.

Abnormalities, Multiple↗
PubMed1984

A screening programme for the prospective prevention of Mediterranean anaemia in Latium: results of seven years' work.

Since 1975 the Rome Microcythaemia Centre has carried out every year, under the auspices of the health authorities of the Latium region, a screening of thalassaemics among intermediate schoolchildren of Latium. From these campaigns, knowledge about thalassaemias among the young adult population has grown which, in its turn, has resulted in screening of these young adults. Through screening in schools between 1975 and 1982, of 289 763 students examined, 6838 thalassaemics were identified, 6045 of whom were beta- or delta beta-thalassaemics. The total number of young thalassaemics who are identified at present in the Centre through screenings of schoolchildren and young adults is about 3300 per year. Furthermore, from January 1980 to April 1983, 110 prospective couples of child-bearing age at risk (94 of whom originated from Latium) were identified at the Centre, and five homozygous fetuses (three of which originated from Latium) were diagnosed. These data derive from an area in which the frequency of thalassaemia is only 2.4%, and they show that the programme in Latium for the prevention of Mediterranean anaemia has been successful.

Adolescent↗
PubMed1984

A study of the mechanisms and sites of action of desferrioxamine in thalassaemia major.

The effects of slow subcutaneous (s.c.) infusions of desferrioxamine (Desferal: DF) on iron metabolism and excretion were studied in 6 thalassaemia major patients in the course of a ferrokinetic study with 59Fe as a label; s.c. DF infusions were performed every 4th day starting 4 days after that of the 59Fe injection. Serum iron and total iron binding capacity (TIBC) increased after s.c. infusion, whereas serum ferritin levels remained unchanged. 59Fe urinary specific activity decreased in all subjects from the first to subsequent infusions, whereas faecal specific activity remained almost constant throughout the experiment. These data support the hypothesis that iron reaching RE cells concentrates initially in a readily chelatable pool from which then it moves to a larger and not readily chelatable pool, whereas iron reaching parenchymal hepatic cells remains permanently available to chelant.

Child↗