Organization of the a-Globin Genes in the Chinese a-Thalassemia Syndromes

group of inherited anemias, the clinical severity of which has been shown to increase with the number ofa-globin structural genes deleted. Employing restriction endonuclease gene mapping, we defined the organization of the a-globin genes in cellular DNA from Chinese subjects with various a-thalassemia syndromes. The four a-globin genes of normals are at two loci located on a 23.0-kilobase pair (kb) Eco RI fragment. In deletion type hemoglobin-H disease the 5 ' a-globin locus is deleted and the single 3 ' a-globin locus is found on a 19.0-kb Eco RI fragment. In a-thalassemia-2 there are two a-globin genes on a 23.0-kb Eco RI fragment and one on a 19.0-kb fragment. In a-thalassemia-I and the nondeletion type of hemoglobin-H disease the two a-globin genes are at two loci on one chromosome and none reside on the other chromosome

Additional file 1. of Discordant circulating fetal DNA and subsequent cytogenetics reveal false negative, placental mosaic, and fetal mosaic cfDNA genotypes

Typical optimized NIPT protocols by Akron Children’s Hospital MFM clinic

Rare Etiology of Autosomal Recessive Disease in a Child with Noncarrier Parents

A child with maple syrup urine disease type 2 (MSUD2) was found to be homozygous for a 10-bp MSUD2-gene deletion on chromosome 1. Both purported parents were tested, and neither carries the gene deletion. Polymorphic simple-sequence repeat analyses at 15 loci on chromosome 1 and at 16 loci on other chromosomes confirmed parentage and revealed that a de novo mutation prior to maternal meiosis I, followed by nondisjunction in maternal meiosis II, resulted in an oocyte with two copies of the de novo mutant allele. Fertilization by a sperm that did not carry a paternal chromosome 1 or subsequent mitotic loss of the paternal chromosome 1 resulted in the propositus inheriting two mutant MSUD2 alleles on two maternal number 1 chromosomes