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J Sequeiros

Publications and source records attributed to J Sequeiros.

43 records · Page 3Linked to original sources
PubMed1985

Linear skin atrophy, scarring alopecia, anonychia, and tongue lesion: a "new" syndrome?

One of a pair of female monozygotic twins showed skin atrophy with linear alternation of depressed scarlike areas and intervening ridges of normal or nearly normal skin. She was born with friable skin and a vesicular-bullous eruption which was followed by gradual scabbing. Hypohidrosis in the affected areas, heat intolerance, and febrile convulsions were noted in infancy and childhood. No new skin lesions developed, and the existing ones, the sweating disturbance, and the heat intolerance gradually improved with time. Scarring alopecia, congenital absence of three toenails, and a scarlike lesion of the tongue were also present. Their absence in the other twin supports the view that 1) these manifestations all are part of the same syndrome, and 2) this syndrome is nongenetic. Histologically, there were no diagnostic or consistent findings, but the number of skin appendages was diminished, and the elastic fibers were reduced in number and size in one biopsy. The calculated probability for the twins being monozygotic was 0.9998. This family was also remarkable for the presence of alopecia areata in three successive generations with only one instance of apparent nonpenetrance. We conclude that this may represent a previously undescribed syndrome of congenital fragility of connective tissue which predisposed to damage of the elastica, possibly caused by an early inflammatory phase.

Alopecia Areata↗
PubMed1984

Machado-Joseph disease in an American-Italian family.

An American-Italian family is described as affected by an autosomal dominant inherited ataxia which meets the clinical diagnostic criteria for Machado-Joseph disease. This disorder no longer appears to be limited to individuals of known Portuguese ancestry.

Adult↗
PubMedDate not supplied

Study of three intragenic polymorphisms in the Machado-Joseph disease gene (MJD1) in relation to genetic instability of the (CAG)n tract.

Intergenerational instability is one of the most important features of the disease-associated trinucleotide expansions, leading to variation in size of the repeat among and within families, which manifests as variable age at onset and severity, and is probably the basis for the occurrence of anticipation. Several factors are known to affect the degree of instability, namely the type of repeated sequence, its initial size, the presence or absence of interruptions in the repetitive tract and the gender of the transmitting parent. A recent study demonstrated the effect of an intragenic polymorphism (C987GG/G987GG) in the Machado-Joseph disease causative gene, immediately downstream of the CAG repeat, on the intergenerational instability of the expanded repeat. Surprisingly, there was an effect not only of the specific allele in cis to the disease chromosome, but also of the allele on the normal chromosome, suggesting the existence of an interaction between the normal and expanded alleles that affects the fidelity of replication of the (CAG)n tract. This effect could be a direct effect of the polymorphism studied or, alternatively, this polymorphism could be in disequilibrium with some other flanking sequence which affects the instability of the repetitive (CAG)n tract. In order to confirm the previous results in a different population and to distinguish between a direct and indirect effect of the CGG/GGG polymorphism, we typed 70 parent-progeny pairs for which the variation in the (CAG)n length in the MJD1 gene was known, for three intragenic polymorphisms: C987GG/G987GG and two additional, newly described ones, TAA1118/TAC1118 and A669TG/G669TG. We also typed a control population of 125 individuals for the A669TG/G669TG, C987GG/G987GG and TAA1118/TAC1118 polymorphisms, in an attempt to identify any association between haplotype and (CAG)n length in normal chromosomes, suggestive of an instability-predisposing effect of the repeat-flanking sequences, which could have led to the origin of the MJD mutation in the human population. We confirmed the effect of the C987GG/G987GG polymorphism on intergenerational instability when present in trans. Our results suggest that this effect is restricted to a small region of the gene, immediately downstream of the CAG repeat, which includes this particular nucleotide substitution and the stop codon of the MJD1 cDNA, and is not a more widespread chromosomal effect. The lack of a significant association of any specific intragenic haplotype with larger CAG repeats in normal chromosomes, together with the absence of an effect of the intragenic haplotype in cis on the intergenerational instability of the expanded (CAG)n in MJD families does not indicate the existence of an instability-predisposing haplotype.

Alleles↗