ABSTRACT
The diagnosis of sudden infant death syndrome (SIDS) has undergone several changes in definition since first being recognised as a cause of death. Linked total population data from Western Australia enable investigations to determine changes in classifications of mortality for the infants of Aboriginal and non-Aboriginal mothers (Aboriginal and Torres Strait Islander people are referred to throughout this report as 'Aboriginal'). Data for recent years show a shift away from a classification of 'SIDS' towards a classification of 'unascertainable', particularly for Aboriginal infants. This has implications for the accurate translation of data into policy and practice.
Subject(s)
Infant Mortality/trends , Native Hawaiian or Other Pacific Islander/statistics & numerical data , Sudden Infant Death/epidemiology , Cause of Death , Humans , Infant , Population Surveillance , Risk Factors , Sudden Infant Death/diagnosis , Sudden Infant Death/ethnology , Western Australia/epidemiologyABSTRACT
Ten cases of small ring chromosomes which did not stain with distamycinA/DAPI and did not possess satellite regions associated with nucleolus-organizing regions are described. In situ hybridization with a battery of biotinylated pericentric repeat probes specific either for individual chromosomes or for groups of chromosomes allowed the identification of the chromosomal origin of these marker chromosomes. There was one example of a marker derived from each of chromosomes 1, 3, 6, 14, 16, 18, 20, 13 or 21, and the X, and there were two examples of markers derived from chromosome 12. One case possessed two markers, one derived from chromosome 6, and one derived from the X. The mechanism of generation of ring marker chromosomes is discussed. Five of seven cases who could be phenotypically assessed were abnormal. Three of these--the first with a ring chromosome derived from chromosome 1; the second with two markers, one derived from chromosome 6 and the other from the X chromosome; and the third with a ring chromosome derived from chromosome 20--each possessed distinctive facies. Additional cases with identified rings may allow the delineation of new chromosomal syndromes.
Subject(s)
Genetic Markers , Ring Chromosomes , Cells, Cultured , Chromosome Banding , Chromosomes, Human, Pair 20/ultrastructure , Chromosomes, Human, Pair 6/ultrastructure , Distamycins , Female , Humans , Infant, Newborn , Karyotyping , Male , Nucleolus Organizer Region , X Chromosome/ultrastructureABSTRACT
In a large kindred in which the gene for central core disease is segregating, we have demonstrated linkage between the disorder and a marker on chromosome 19q. Marker D19S9 (p1J2) was linked to central core disease with a lod score of 6.4 at theta = 0.03 (support interval 0.01-0.14) thus localizing the gene for this disorder in or very close to 19q12-q13.2.
Subject(s)
Chromosomes, Human, Pair 19 , Genetic Linkage , Muscular Diseases/genetics , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Genes, Dominant , Genetic Markers , Humans , Lod Score , Male , Middle Aged , Pedigree , Restriction MappingABSTRACT
Nine cases are described of tetrasomy 18p resulting from the presence of an isochromosome 18p [i(18p)]. The initial diagnosis of i(18p) was by standard cytogenetic techniques and was confirmed by in situ hybridization with a biotinylated alphoid probe (L1.84) specific for the pericentric region of chromosome 18 and with a tritium-labeled chromosome 18 probe (B74) which hybridizes to the D18S3 locus situated at 18p11.3. The clinical features of the cases are summarized and shown to constitute a distinct and recognizable syndrome. Common features were low birth weight, a characteristic facies, neonatal hypotonia with subsequent limb spasticity, short stature, microcephaly, mental retardation, and seizure disorders. On the basis of size and cytogenetic banding a marker chromosome can be suspected to be an i(18p). In situ hybridization with the alphoid probe L1.84 provides confirmation of chromosome 18 origin. This more precise diagnosis will be an advantage in situations of pre- and postnatal diagnosis, since parents can be provided with a more confident prognosis for their child.
Subject(s)
Abnormalities, Multiple/genetics , Chromosome Aberrations/genetics , Chromosomes, Human, Pair 18 , Adolescent , Adult , Child , Chromosome Banding , Chromosome Disorders , Female , Humans , Infant, Newborn , Karyotyping , Male , Nucleic Acid Hybridization , SyndromeABSTRACT
Three patients with different marker chromosomes were screened by in situ hybridisation using biotinylated probes to chromosome specific pericentric repeats to determine the chromosomal origin of the marker. Each marker had a different origin, with one from each of chromosomes 1, 9, and 16. This is the first time that autosomal marker chromosomes consisting of a small ring have been shown to be derived from the pericentric heterochromatin of metacentric and submetacentric chromosomes. Evidence suggests that such markers are not associated with any significant risk of phenotypic abnormalities, but additional cases need to be studied.
