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Biomedical subjects

R Mingarelli

Publications and source records attributed to R Mingarelli.

At least 55 records · Page 3Linked to original sources

Two sisters with a syndrome of ocular, skeletal, and abdominal abnormalities (OSA syndrome).

Two adult sisters are described who had a unique association of facial, ocular, and skeletal defects, and abdominal muscle hypoplasia, indicating autosomal recessive inheritance. Many of these features overlap those previously found in other malformation syndromes. However, the constellation of defects observed in these patients appears to represent a previously unreported syndrome and autosomal recessive inheritance is likely.

Abdomen↗

Human homologue sequences to the Drosophila dishevelled segment-polarity gene are deleted in the DiGeorge syndrome.

DiGeorge syndrome (DGS) is a developmental defect of some of the neural crest derivatives. Most DGS patients show haploinsufficiency due to interstitial deletions of the proximal long arm of chromosome 22. Deletions of 22q11 have also been reported with patients with the velocardio-facial syndrome and familial conotruncal heart defects. It has been suggested that the wide phenotype spectrum associated with 22q11 monosomy is a consequence of contiguous-gene deletions. We report the isolation of human cDNAs homologous to the Drosophila dishevelled (dsh) segment-polarity gene. Sequences homologous to the 3' UTR of these transcripts (DVL-22) were positioned within the DGS critical region and were found to be deleted in DGS patients. Human DVL mRNAs are expressed in several fetal and adult tissues, including the thymus and, at high levels, the heart. Two transcripts, 3.2 and 5kb, were detected, in northern blot analysis, with different expression patterns in the surveyed tissues when different cDNAs were used. The isolated cDNAs exhibit high amino acid homology with the mouse and Xenopus Dvl-1 gene, the only other vertebrate dsh homologues so far isolated. The pivotal role of dsh in fly development suggests an analogous key function in vertebrate embryogenesis of its homologue genes. Since DGS may be due to perturbation of differentiation mechanisms at decisive embryological stages, a Dsh-like gene in the small-region overlap (SRO) might be a candidate for the pathogenesis of this disorder.

Adaptor Proteins, Signal Transducing↗

[Genetic aspects of deafness].

Congenital sensorineural hearing impairment affects approximately 1 in 1000-2000 children and is of genetic origin in at least one half of these cases. Over 70% of congenital sensorineural hearing impairment is non-syndromic while, about 30% is associated with other defects. Over 75% of congenital non-syndromic hearing sensorineural hearing impairment is autosomal recessive and to date at lest ten loci have been implicated. The remaining forms are transmitted in an autosomal dominant, or X-linked (2%) manner. Some congenital types of hearing impairment are also due to chromosomal aneuploides or mitochondrial DNA mutations. Although different loci associated with hearing impairment have been mapped to specific chromosomic regions, the cloning and the functional characterization of these genes is not immediate.

Aneuploidy↗

Myoclonic epilepsy, neuroblast migration disorders, and maternally derived partial duplication 14q/deletion 15q.

A large maternally inherited duplication of 14q and deletion of proximal 15q was observed in a child with myoclonic epilepsy, mental retardation and neuroblast migration disorders (NMDs) detected by MRI. Genetic syndromes associated with NMDs have previously been described. In additional our observations support the connection between major chromosomal imbalances, developmental brain disorders and epilepsy. Thus, in patients with these combinations of symptoms, careful chromosome investigations are recommended.

Cell Movement↗

Two pedigrees of autosomal dominant atrioventricular canal defect (AVCD): exclusion from the critical region on 8p.

Atrioventricular canal defects (AVCD) constitute the predominant congenital heart defect in Down syndrome. For this reason, a candidate gene involved in atrioventricular canal development was previously searched and excluded in dominant pedigrees of AVCD, using linkage analysis of polymorphisms from chromosome 21. Because of the striking association between 8p deletion and AVCD, a search for an AVCD gene was carried out in two pedigrees of individuals with autosomal dominant AVCD using a set of DNA markers of the 8pter-->q12 region. These two families include affected individuals and subjects who have transmitted the defect but are not clinically affected. Two-point lod scores were significantly negative for all markers at penetrance levels of 90% and 50%. Multipoint analysis excluded the region covered by the markers LPL-D8S262 and 30 cM to either side of this area. This result corroborates heterogeneity of this heart defect and indicates that the genetic basis of familial AVCD is different from AVCD associated to either trisomy 21 or 8p deletion.

Child↗

Fetal translocation between chromosomes 2, 18, and 21 resolved by fish.

An apparently balanced t(2q;21q) translocation was discovered in fetal blood and amniocytes of a 22-week fetus, monitored because of ultrasonographic evidence of a heart disease. FISH (fluorescence in situ hybridization) analysis disclosed a complex translocation between chromosomes 2q, 18q, and 21q, which was inherited from the healthy mother. This observation corroborates the usefulness of molecular cytogenetic techniques in raising the quality of prenatal diagnosis and detecting subtle rearrangements not resolved by standard cytogenetics.

Adult↗

Analysis of the elastin gene in 60 patients with clinical diagnosis of Williams syndrome.

Williams syndrome (WS) is caused by deletion of the elastin (ELN) gene. We have analyzed an intragenic restriction fragment length polymorphism (RFLP) and the gene dosage of ELN using a new probe (FP4) in a series of 60 sporadic patients with a clinical diagnosis of WS. Deletion of the ELN gene was shown in 54 cases, while clinical revaluation of the 6 patients without the deletion did not confirm the diagnosis of WS. These results support the genetic homogeneity of WS, and the high accuracy of ELN molecular analysis, which can be confidenty used for providing genetic counselling to WS families.

Adolescent↗

22q11 deletions in isolated and syndromic patients with tetralogy of Fallot.

Tetralogy of Fallot (TF) is a congenital conotruncal heart defect commonly found in DiGeorge (DGS) and velo-cardio-facial (VCFS) syndromes. The deletion of chromosome 22q11 (del22q11) is a well established cause of DGS and VCFS, and it has been demonstrated also in sporadic or familial cases of TF. In order to investigate the prevalence of del22q11 in patients with TF, we analyzed the DNA of 137 consecutive patients with syndromic and isolated TF, using the HD7k probe, which detects hemizygosity for the D22S134 locus. Del22q11 has been detected in 11/26 (42%) syndromic patients. Evidence for hemizygosity was obtained in all patients with DGS and in 8/15 patients with VCFS. None of the 107 patients with isolated TF had del22q11. Our experience suggests that children with TF and del22q11 always present major or minor extracardiac anomalies. These features, including subtle facial dysmorphisms, should be checked routinely in patients with TF and other conotruncal heart defects.

Adolescent↗

The link between cytogenetics and mendelism.

High resolution chromosome analysis, molecular cytogenetics, and study of the association between specific chromosome rearrangements and single gene disorders have provided a chromosomal basis to a number of mendelian diseases. Deletions and duplications of small regions, usually less than 3 Mb in size, result in an alteration of normal gene dosage of a number of unrelated genes physically close to each other and are responsible for contiguous gene syndromes. For example, haploinsufficiency is implicated for del 8q24.1 in Langer-Giedion syndrome, del 17p13.3 in Miller-Dieker syndrome, and del 22q11.2 in DiGeorge and Velo-cardiofacial syndromes. Another chromosomal mechanism causing mendelian phenotypes is translocation, which may eventually interrupt a disease gene. It is assumed that translocation breakpoints are running through a relevant gene, hindering the production of the gene product. An example is breakage 16p13.3 associated with Rubinstein-Taybi syndrome. Females with X/autosome translocations have an almost exclusive inactivation of the normal X. Interruption of a disease gene in the translocated X causes the expression of a mendelian phenotype in the presence of an allelic recessive mutation onto the nonrearranged X. Finally, if a human gene shows exclusive expression from a single parental homologue, ie, it is imprinted, deletion of the chromosomal segment containing the active allele results in structural monosomy and functional nullisomy. This situation is illustrated by Prader-Willi and Angelman syndromes. Over seventy human genes have been precisely assigned to chromosomal regions using a cytogenetic approach. Chromosome techniques combined with molecular methods have proved to have powerful and sensitive diagnostic capabilities.

Chromosome Deletion↗

Sporadic trichodental dysplasia with microcephaly and mental retardation.

Trichodental syndrome is a rare autosomal dominant ectodermal dysplasia. Hair and dental anomalies have been found in different combinations in most affected persons in three families. The features of trichodental syndrome were observed in a young female in which sparse, fine, lustreless and slow growing hairs were associated with bigeminismus of inferior lateral incisors. Ultrastructural hair analysis showed consistent variation in contour of the shaft and reduced to absent cuticular scale. Distinguishing features in this patient were microcephaly and mild mental retardation.

Child, Preschool↗

Joint dislocation and cerebral anomalies are consistently associated with oral-facial-digital syndrome type IV.

We present a female patient with the oral-facial-digital syndrome type IV. Our report, the tenth in the literature, describes the typical manifestations of the syndrome, combined with malformations and deformations which have not always been described in the previously reported cases. They include cerebral and renal anomalies, anal atresia and dislocation of elbows and knees.

Abnormalities, Multiple↗

Duplication Xp22.2 and pseudoisodicentric Yq detected by FISH and PCR in a sterile male.

A chromosome mosaicism with two cell lines was diagnosed in a sterile man. One cell line had a 45, -Y, dup (X) (p22.2) karyotype and accounted for 83% of lymphocytes analyzed. Fluorescence in situ hybridization (FISH) analysis with specific X and Y probes excluded a translocation between the short arms of the X and Y chromosomes and showed that Xp duplication involved a region containing the DXS85 locus, distal to the ZFX and DSS sites. The other cell line consisted of a diploid karyotype with a rearranged Y chromosome, which was shown to be a pseudoisodicentric Yq by FISH. Moreover, FISH with a specific probe for the AZF locus and polymerase chain reaction using Yq SY108 and SY121 primers showed no signals for this region, possibly accounting for the azoospermia in this patient.

Adult↗

An autosomal recessive syndrome of cleft palate, cardiac defect, genital anomalies, and ectrodactyly (CCGE).

We report a brother and sister affected by a constellation of malformations, including cleft palate, cardiac defect, genital anomalies, and ectrodactyly (CCGE). A similar association has been reported previously by Richieri-Costa and Orquizas in a male patient born to consanguineous parents. An autosomal recessive pattern of inheritance is proposed for this syndrome.

Abnormalities, Multiple↗