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Biomedical subjects

S H Roberts

Publications and source records attributed to S H Roberts.

At least 37 records · Page 2Linked to original sources

Recognition and reanalysis of a cell line from a manifesting female with X linked hypohidrotic ectodermal dysplasia and an X; autosome balanced translocation.

We have restudied a fibroblast cell line from a female with marked manifestations of X linked hypohidrotic ectodermal dysplasia (HED) and a balanced X;9 translocation. Chromosome analysis showed a karyotype of 46,X,t(X;9)(q13.1;p24) with an Xq breakpoint distal to the one previously reported. The significance of the cell line, previously unrecognised, for the mapping and eventual cloning of the HED locus is discussed.

Cell Line↗

Interstitial deletion of 17p11.2: case report and review.

A child with mental retardation and multiple congenital abnormalities, including brachycephaly, an unusual facies, brachydactyly, clinodactyly and bilateral talipes valgus, was found to have a small interstitial deletion of the short arm of chromosome 17. The clinical features and cytogenetic observations are compared with those in previously reported cases.

Abnormalities, Multiple↗

A new variant of chromosome 16.

A new variant of chromosome 16 with an additional C-band negative segment in the proximal region of the short arm is described. This variant chromosome was found in four cases, two of which were detected prenatally. In three probands the variant chromosome 16 was inherited from a phenotypically normal father.

Adult↗

Homozygous paracentric inversion 12 in a mentally retarded boy: a case report and review of the literature.

A mentally retarded male was found to be homozygous for a paracentric inversion of the long arm of chromosome 12(inv(12)(q21.1q23.2]. His parents, who are first cousins, and his phenotypically normal younger brother are inversion heterozygotes. Homozygous structural rearrangements are discussed and cases of paracentric inversions, including a further nine previously unpublished, are reviewed.

Adolescent↗

Further mapping of markers around the centromere of human chromosome 19.

The gene for myotonic dystrophy (DM) is located on the proximal long arm of chromosome 19 along with at least 10 cloned genes and anonymous DNA segments. In order to refine the map of this region of the chromosome, we have constructed somatic cell hybrid lines from fibroblasts carrying a balanced translocation t(1, 19) with a breakpoint at 19q12. We have established that D19S7 is the most proximal of the available long-arm markers and confirmed that PEPD localizes to 19q, along with PVS, MSK19, and MSK37. We have also examined the segregation of markers from the proximal long-arm region of chromosome 19 in hybrids containing fragments of this chromosome.

Animals↗

Duchenne muscular dystrophy with adrenal insufficiency and glycerol kinase deficiency: high resolution cytogenetic analysis with molecular, biochemical, and clinical studies.

A syndrome of Duchenne muscular dystrophy (DMD), adrenal hypoplasia, glycerol kinase deficiency, and mental retardation has been recognised. We report a further case ascertained from a history of DMD, severe mental retardation, and an Addison-like disorder. Cytogenetic analysis of the proband revealed an interstitial deletion of the short arm of the X chromosome. from Xp21.1 to Xp22.11, comprising about 9% of the length of the normal X chromosome. His mother was heterozygous for the deletion, but his maternal grandmother and sister both had two normal X chromosomes. DNA probe analysis confirmed the existence of a deletion in the affected boy, as probes 754, C7, XJ1-1, and pERT87 consistently failed to hybridize to his DNA. His sister was heterozygous for the RFLP associated with 754, thus confirming that she had two normal X chromosomes. There was no evidence of chronic granulomatous disease, other immunological defect, or retinitis pigmentosa in this case. Biochemical studies revealed gross glyceroluria and hyperglycerolaemia, indicating glycerol kinase deficiency which has been confirmed enzymatically. We have subsequently screened 21 other boys with DMD for glyceroluria and found one other case. Cytogenetic analysis has also been performed in nine other families, where a boy with DMD has been shown to have a deletion of DNA sequences localised to the region Xp21. None of these cases demonstrated any cytogenetic abnormality, nor has their clinical course been unusual.

Adolescent↗

Assignment of human ferritin genes to chromosomes 11 and 19q13.3----19qter.

Extracts of hamster-human and mouse-human hybrids, some with translocations involving chromosome 19, have been assayed for both human spleen ferritin (rich in L subunits) and human heart ferritin (rich in H subunits). Hybrid lines retaining part of the long arm of chromosome 19 including the region 19q13.3----19qter produced human "L" type ferritin. This confirms the previous assignment of the "ferritin gene" to chromosome 19 (Caskey et al. 1983). However, lines retaining chromosome 11 were found to contain human "H" type ferritin suggesting that the gene for the "H" subunit is on this chromosome. The presence of chromosome 6 was not necessary for the expression of either "H" or "L" type human ferritin. It thus seems unlikely that the gene for idiopathic haemochromatosis is a ferritin gene.

Animals↗

Unbalanced reciprocal translocations in cases of Prader-Willi syndrome.

A case of Prader-Willi syndrome (PWS) associated with a de novo unbalanced 15q;17q reciprocal translocation presumptively resulting from the tertiary monosomic form of 3:1 meiotic disjunction is described. Twenty-three similar unbalanced translocations have been identified from the literature. The 24 karyotypes are characterised by having 45 chromosomes, monosomy for the pericentromeric region of chromosome 15 (range pter----q11 to q21), and little monosomy of the recipient (non-15) chromosome. Two-thirds of the cases with these karyotypes have phenotypic features of PWS. It seems probable that (i) where unbalanced reciprocal translocations are associated with PWS, they will almost invariably be presumptive segregants of the tertiary monosomic form of 3:1 disjunction and (ii) the majority of cases found with this type of karyotype, particularly it appears when de novo in origin, will be associated with phenotypic features of PWS.

Child, Preschool↗

Adjacent 2 meiotic disjunction. report of a case resulting from a familial 13q;15q balanced reciprocal translocation and review of the literature.

An abnormal short-lived female infant with almost complete trisomy 13 (pter leads to q32 or 33) and partial monosomy 15 (pter leads to q14 or 15) resulting from an adjacent 2 meiotic disjunction of a paternal reciprocal translocation is described. Cases with monosomy of chromosome 15 material are reviewed. It appears likely that monosomy of an interstitial long arm segment, approximating to 15q21 leads to 24, imparts the lethality associated with the full monosomic condition. Adjacent 2 disjunction in man has been further characterised by reviewing the literature.

Abnormalities, Multiple↗

Partial trisomy 12q: report of a case and review.

A malformed male infant with pure partial trisomy 12q (q24.1 leads to qter), resulting from an unbalanced segregation of a paternal balanced translocation t(2;12)(q37;q24.1), is described. The cytogenetic and clinical abnormalities of the proband are compared with those of four previously reported cases of partial trisomy 12q, two of which also appear to have pure trisomy of segment 12q24.1 leads to 12 qter.

Abnormalities, Multiple↗

A new pericentric inversion of chromosome 6 in an abnormal infant.

An apparently de novo case of a previously unreported pericentric inversion of a No. 6 chromosome present in an abnormal infant is described. The possibility of an association between the abnormal karyotype and phenotype is discussed. The authors express the desirability for precise documentation of balanced chromosomal rearrangements.

Abnormalities, Multiple↗