Abstract:
Fifteen patients were referred with provisional diagnosis of intersex from
hospitals or private clinics of different geographical regions in Sudan to the
Department of Clinical Genetics at the Radiation and Isotopes Center, Al
Neelain Medical Research Center, and Elite Clinic for cytogenetic and/or
molecular diagnosis. Of the 15 patients, 11 of them (73.3%) were raised as
females, while 4 of them (26.7%) were raised as males; those patients were
diagnosed by The Sudanese Intersex Working Group according to the
medical history, physical examination, ultrasound, hormonal analysis,
cytogenetic, and molecular studies.
The aim of this study was to determine the value of molecular analysis using
SRY and Amelogenin genes in sex determination among patients with sex
differentiation disorders by detection of presence or absence of SRY gene
(sex determining region on Y chromosome) and findings of amelogenin
gene (amelogenin gene found in both X and Y chromosomes with different
molecular weights) in association with karyotyping.
Venous blood samples were taken from every patient to detect the presence
or absence of SRY gene and the amelogenin gene findings compared with
the karyotyping of all patients.
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DNA extraction was done and then PCR (polymerase chain reaction) was
held to detect the presence or absence of SRY gene and amelogenin gene
findings (either indicate XX or XY chromosomes).
The results of this study showed that 12 patients (80%) found to have XY
karyotype, SRY positive and amelogenin findings showing XY pattern. One
patient (6.7%) had XY chromosomes, SRY present, and amelogenin
findings showing XX. Another patient (6.7%) resulted in XX chromosomes,
SRY present, and amelogenin findings indicated presence of XY
chromosomes. The last patient (6.7%) had a mosaic karyotype (XX/XY),
SRY positive and the amelogenin findings showed XY pattern.
These results indicated that the sex determination can never be based on the
detection of amelogenin gene alone, but rather on the karyotyping and SRY
gene, because the amelogenin gene never tells about mosaic conditions and
SRY gene translocation, while karyotyping and SRY gene do.
