Cytogenetic investigation of patients with primary amenorrhea.

Primary amenorrhea refers to absence of spontaneous menarche even after the age of 16. Cytogenetic analysis in two cases with primary amenorrhea, short stature, poorly developed secondary sexual characteristics, and growth retardation were studied. Routine GTG-band analysis of metaphases from peripheral blood leucocytes revealed female karyotype with a 15(ps+) and an isochromosome of X, i(Xq), in one patient and 46,X, i(Xq), in another patient. Ascertainment of the karyotype aided in confirmation of the provisional diagnosis, a better phenotype–genotype correlation to understand clinical heterogeneity in genetic counseling.

Isochromosome X mosaicism in a child with Kabuki syndrome phenotype: A rare cytogenetic association.

Isochromosome is a structurally unbalanced chromosome consisting of two short arms or two long arms, which are derived by abnormal centromere division or sister-chromatid exchange. Most autosomal isochromosomes are unusual, while those involving sex chromosomes are common. Kabuki syndrome (KS, OMIM 147920) is a multiple malformation/mental retardation syndrome of unknown etiology. A conventional cytogenetic study on lymphocytes from a 4-year-old girl with physical features suggestive of KS was found to have mosaicism for isochromosome for the long arm of the X. Although most manifestations present in this patient have been described before, this report is a rare association of clinical and cytogenetic findings in this syndrome. A genome-wide analysis and a larger number of patient groups studied could improve our understanding of the genetic basis of KS.