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Biomedical subjects

D Sillence

Publications and source records attributed to D Sillence.

At least 37 records · Page 2Linked to original sources
PubMed1995

Genetic homogeneity of cartilage-hair hypoplasia.

Cartilage-hair hypoplasia (CHH) is an autosomal recessive metaphyseal chondrodysplasia characterized by short stature and hypoplasia of the hair. Associated pleiotropic features include deficient erythrogenesis, impaired T-cell mediated immunity, Hirschsprung's disease, and an increased risk of malignancies. CHH is most prevalent among the Old Order Amish in the United States and among the Finns, but sporadic families have been described among many other populations. We have previously mapped the gene for CHH to the short arm of chromosome 9 in Finnish and Amish families. The CHH locus resides close to D9S163 within an interval of 1.5 cM flanked by D9S165 and D9S50. In order to investigate the genetic homogeneity of CHH in various populations, we studied nine families with no genealogical connections to either Amish or Finns. No recombinants were detected between the CHH gene and any of the three closest marker loci studied, suggesting that CHH in these families results from mutation(s) at the same locus as in the Amish and Finnish families.

Canada↗
PubMed1995

Increased instability of intermediate alleles in families with sporadic Huntington disease compared to similar sized intermediate alleles in the general population.

We have directly compared intergenerational stability of intermediate alleles (IAs) derived from new mutation families (IANM) for Huntington disease (HD) with IAs in the general population (IAGP) which occur in approximately 1 in 50 persons. Analysis of meiotic events in blood and sperm reveals that IANM are significantly more unstable than IAGP despite similar size. However, for both IANM and IAGP CAG changes were small and risks for inheriting an expansion into the HD affected range were low. Sequence analysis reveals that the CAG tract is generally interrupted by a penultimate CAA in IAGP, IANM and alleles in the affected range. In one new mutation family, however, two A-->G mutations result in a pure CAG tract which is associated with very marked instability. These mutations alter the predicted DNA hairpin structure with a predicted increase in the likelihood of large expansion, supporting the model that hairpin loop formation plays an important role in trinucleotide instability.

Alleles↗
PubMed1994

Novel karyotype in the Ullrich-Turner syndrome--45,X/46,X,r(X)/46,X, dic(X)--investigated with fluorescence in situ hybridization.

A 10-year-old girl with Ullrich-Turner syndrome was found to have the novel karyotype 45,X/46,X,r(X)(p11q11)/46,X,dic(X)(p11). Fluorescence in situ hybridization (FISH) with the alpha satellite X centromere probe established the origin of the small ring chromosome. Scanning a large number of cells by interphase FISH showed that the dicentric (X) was the least prevalent cell line. The common breakpoint of Xp11 suggests a sequence of errors as the mechanism whereby these 3 distinct cell lines have arisen.

Cells, Cultured↗
PubMed1994

Bone mineral density of total body, spine, and femoral neck in children and young adults: a cross-sectional and longitudinal study.

Bone mineral density (BMD) of total body (TBMD), lumbar spine (L2-4), and femoral neck was measured in 266 normal subjects (136 males) aged 4-27 years (mean 13 years) using dual-energy x-ray absorptiometry (DXA). BMD of all sites increased significantly with age until 17.5 years in males and 15.8 years in females, except for femoral neck BMD in females, which peaked at age 14.1 years. Males had higher peak TBMD, which was attributed to greater weight and lean tissue mass. In contrast, despite a later timing, peak L2-4 BMD in males was not different from that in females. Before peak BMD, weight was the best predictor of TBMD and L2-4 BMD in both sexes (r2 ranged from 0.77 to 0.88), whereas femoral neck BMD was predicted equally by height and weight. Longitudinal information collected from 53 (25 boys) of these children, aged 4-16.9 years, showed that the average annualized gain in TBMD was 0.047 g/cm2 for boys and 0.039 g/cm2 for girls. No significant difference in the association between age and BMD (slopes) was found between cross-sectional and longitudinal data for either sex. We conclude that the timing for peak BMD was consistent for total body, lumbar spine, and femoral neck for each sex. The earlier peak BMD in females is most likely related to earlier puberty. The cross-sectional normative data of this study are useful in serving as a standard for serial assessment in health and disease states.

Absorptiometry, Photon↗
PubMed1994

Case report 870. Schneckenbecken dysplasia, possibly a new variant.

We report the case of a newborn with a lethal newborn skeletal dysplasia, in whom skeletal and morphologic findings resembled those in schneckenbecken dysplasia except that the projection of bone from the medial aspect of the iliac bones, resembling the "snail's" head, was absent. This could be accounted for by variability or genetic heterogeneity.

Bone and Bones↗
PubMed1994

Mesomelic dysplasia: Langer type.

Two patients with Langer type mesomelic dysplasia are reported. This is one of the rare but well differentiated and easily recognizable mesomelic dysplasias.

Adult↗
PubMed1994

X linked mental retardation with non-deletional alpha thalassaemia (ATR-X): further delineation of the phenotype.

Two sibs with non-deletional alpha thalassaemia and mental retardation (ATR-X) have been ascertained showing variable neurological features. The proband had a complex neurological picture with recurrent apnoea, complex partial seizures, and prolonged periods of semiconsciousness between 12 and 17 months of age. Episodes of spontaneous laughter were also a feature. An EEG was initially normal. Hb H inclusions were present but rare in this family. The sole genital anomaly was deficiency of the foreskin, a feature not previously described in ATR-X.

Abnormalities, Multiple↗
PubMed1993

Natural history of blue sclerae in osteogenesis imperfecta.

Scleral hue is an important sign which distinguishes 2 broad groupings of patients, those with and those without blue sclerae with nonlethal osteogenesis imperfecta (OI). Individuals with OI type I have distinctly blue sclerae which remain intensely blue throughout life. In OI type III and OI type IV the sclerae may also be blue at birth and during infancy, but the intensity fades with time such that these individuals have sclerae of normal hue by adolescence and adult life.

Adolescent↗
PubMed1993

Breathing abnormalities in sleep in achondroplasia.

Overnight sleep studies were performed in 20 subjects with achondroplasia to document further the respiratory abnormalities present in this group. Somatosensory evoked potentials (SEPs) were recorded in 19 of the subjects to screen for the presence of brainstem abnormalities, which are one of the potential aetiological mechanisms. Fifteen children aged 1 to 14 years, and five young adults, aged 20 to 31 years were included. All had upper airway obstruction and 15 (75%) had a pathological apnoea index (greater than five per hour). Other sleep associated respiratory abnormalities, including partial obstruction, central apnoea, and abnormal electromyographic activity of accessory muscles of respiration, also showed a high prevalence. SEPs were abnormal in eight (42%), but there was no correlation between abnormal SEPs and apnoea during sleep, either qualitatively or quantitatively. A high prevalence of both sleep related respiratory abnormalities and abnormal SEPs in young subjects with achondroplasia was demonstrated. However, the sleep related respiratory abnormalities do not always result in significant blood gas disturbances or correlate with abnormal SEPs in this group.

Achondroplasia↗
PubMed1992

Ultrastructure and immunocytochemistry of hepatic peroxisomes in rhizomelic chondrodysplasia punctata.

Peroxisomes were studied in the liver of two rhizomelic chondrodysplasia punctata patients using electron microscopy and catalase cytochemistry. Immunoelectron microscopy was carried out on the liver of one of these patients using antibodies to catalase, acyl-CoA oxidase, bifunctional protein, 3-ketoacyl-CoA thiolase and a 68 kDa peroxisomal membrane protein, in conjunction with protein-A colloidal gold. Moderately to markedly enlarged, flocculent peroxisomes were found in both patients. In one patient they were very heterogeneous with regard to the number per hepatocyte. The peroxisomes had very low levels of catalase as indicated by cytochemistry and immunocytochemistry. The three beta-oxidation enzymes were localised normally within the peroxisomes. The 68 kDa membrane protein was localised to the peroxisomal membranes. Some extra membrane loops were also identified using this antibody.

3,3'-Diaminobenzidine↗
PubMed1992

A new syndrome? Unusual facies, hooked clavicles, 13 pairs of ribs, widened metaphyses, square shaped vertebral bodies and communicating hydrocephalus.

Two strikingly similar twin sisters presented with characteristic facial anomalies and distinctive radiographic findings. The occurrence of this unique pattern of malformations in two sisters with unaffected parents suggests recessive inheritance. They most likely represent a previously unrecognised malformation syndrome.

Abnormalities, Multiple↗
PubMed1992

Familial Scheuermann disease: a genetic and linkage study.

Scheuermann juvenile kyphosis or Scheuermann disease is the most frequent cause of kyphosis in adolescence. However, the natural history and genetic basis is still unknown. Reports of identical radiological changes in monozygotic twins, sib recurrence, and transmission over three generations suggest underlying heritability. In this study, 12 probands were referred to us. Upon radiological examination of the proband's parents and sibs, seven were shown to have familial Scheuermann disease with an autosomal dominant pattern of inheritance. Of the remaining five probands, four had chromosomal anomalies. The three largest pedigrees were subjected to linkage analysis with three candidate genes: Duffy, COL1A1, and COL1A2. Linkage of Scheuermann disease was excluded with Duffy (lod score = -2.195 at theta = 0.10) and COL1A2 (lod score = -2.750 at theta = 0.05) in these families.

Adolescent↗
PubMed1991

Lumbar platyspondyly--characteristic sign of Ehlers-Danlos syndrome.

Three patients with Ehlers-Danlos syndrome have been observed to have isolated flattening of the lumbar vertebral bodies. Flattening of the lumbar vertebrae with normal appearance of the rest of the spine may be an important radiological clue to early recognition or confirmation of the diagnosis of Ehlers-Danlos syndrome.

Adolescent↗
PubMed1988

The rib gap anomaly in partial or mosaic trisomy 8.

Gaps in the first ribs were observed in two children, one with partial and the other with mosaic trisomy for chromosome 8. The sign may be considered in conjunction with other features as a relative indication for chromosomal studies.

Bone and Bones↗