title: Absence of constitutive heterochromatin in a partially identified supernumerary marker chromosome.
abstract: A retarded child with multiple malformations was found to have a karyotype 47,XY,de1(11)(11 pter leads to q21:), +mar(11 qter leads to q21::?). The mitotically stable centric marker had no demonstrable C heterochromatin. Phenotype-karyotype correlation and the role of C heterchromatin in phenotypic effects are discussed.
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D002871:Chromosome Banding; D002877:Chromosomes, Human / Q000648:ultrastructure*; D005819:Genetic Markers; D006570:Heterochromatin / Q000648:ultrastructure*; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D008297:Male; D010641:Phenotype
chemical_list: D005819:Genetic Markers; D006570:Heterochromatin