Detection and localization of an extra HLA locus in a karyotypically normal male by chromosomal in situ hybridization

Abstract

The codominant expression of three HLA haplotypes was found in a healthy 21‐year‐old Black male, whose prometaphase karyotype was normal by light microscopy. He was the sibling of an antenatally diagnosed female fetus with a partial duplication of 6p. The duplication arose from a complex presumably balanced maternal chromosome rearrangement: 46, XX, dir ins(14;6)(14pter→14p11::6p22→6p21.1::14p11→14qter;6pter→6p22::6p21.1→6qter). Chromosomal in situ hybridization using a tritium‐labeled genomic clone corresponding to a class I HLA gene revealed two sites of hybridization: at 6p21.3, the band to which this probe has been assigned in normal individuals (Morton et al. 1984a) and a second site at 6p11. We postulate that a recombinational event during meiotic pairing in the mother led to the reintroduction into the normal chromosome 6 homolog of a small segment of the original insertion in chromosme 14 which contained the HLA‐A and ‐B determinants.

Cytogenetics of Prader‐Willi Syndrome

“…Since a small deletion or duplication due to an unequal crossing-over in conjunction with a parental balanced rearrangement may not be associated with a corresponding rearrangement (Hoo 1983, Morton et al 1982, it is conceivable that a PWS patient with no visible chromosome aberration may have a parent with a microscopically visible balanced rearrangement involving chromosome 15. Consequently, high resolution chromosome analysis on the parents may also be indicated, even though the chromosomes 15 of the patient appear normal.…”

Phytocompounds Targeting for the Treatment of β-Thalassemia: A Review

“…The HBB gene provides instructions for making a part of haemoglobin [Morton et al, 1984], which is the protein in red blood cells that carries oxygen throughout the body [Gell, 2018].…”

When a synonymous mutation breaks the silence in a thalassaemia patient

“…1 Haemoglobin consists of a pair of β-globin and α-globin chains, which together form adult haemoglobin (HbA). 2 Mutations in the HBB gene result in an inherited recessive blood disorder that alters the gene at the transcriptional or translational level and affects the stability and production of the β-globin chain, leading to β-thalassaemia. 3,4 β-Thalassaemia is one of the most common genetic disorders in India.…”