RESUMO
A 30 years old female with premature ovarian failure [POF] was referred to the cytogenetic lab for chromosome analysis because of secondary amenorrhea. She appeared to be normal with no stigmata of Turner syndrome There was no family history of any reproductive abnormalities. Routine G-band chromosome analysis showed an abnormal female karyotype with mosaicism for X-chromosome. Twenty-two of the 45 metaphases analyzed had 45,X chromosome complement while the remaining 23 metaphases had 46 chromosomes with one normal X chromosome and one pseudo isodicentric X chromosome involving breakpoint at Xq26.X-chromosome mosaicism and/or deletions involving Xq is usually associated with abnormal sexual development and reproductive performance often with POF. Two specific regions on Xq have been defined in the literature as POF loci, POFI at Xq26-q28 and POF2 at Xq13.3-q21. detail clinical assessment of our patient revealed the presence of possible functional oocytes and she opted for IVF. Variant Turner with mosaicism involving pseudo isodicentric [x] [q26] is very rare. Possible mechanism of the origin of the two cell lines and their correlation with POF in our patient is discussed