Turner syndrome other diagnostic studies

The diagnostic study of choice for the diagnosis of Turner syndrome is karyotype analysis of 30 blood lymphocytes. Findings may include the classic 45 XO karyotype, mosaicism and structural anomalies like isochromosomes or ring chromosomes.

• The diagnostic study of choice for the diagnosis of Turner syndrome is karyotype analysis of 30 blood lymphocytes.
• Findings may include the classic 45 XO karyotype, mosaicism and structural anomalies like isochromosomes or ring chromosomes.
• If an abnormality associated with Turner syndrome is diagnosed by ultrasonography or if multiple marker screening is positive, the recommended follow-up is fetal karyotyping using amniotic fluid cells obtained by amniocentesis or fetal blood obtained by percutaneous umbilical blood sampling when the karyotype is needed more rapidly.
• The karyotype does not determine the phenotype.
• The standard 30 cell karyotype analysis should be performed if a single clinical feature (short stature, hydrops fetalis, cystic hygroma, characteristic facial features) or two commonly associated conditions (Madelung deformity, cardiac or renal anomalies, multiple nevi) are seen. ^[1]
• In patients with virilization but absent Y chromosomal abnormalities on initial analysis, fluorescent in situ hybridization (FISH) or PCR techniques specific for cryptic Y material maybe performed. ^[2]
• Females with short stature and deletion of the distal region of the paternal X chromosome including the SHOX gene are generally not diagnosed with Turner syndrome.
• Similarly, individuals with deletions of Xq24, with primary or secondary amenorrhea and without short stature are diagnosed as premature ovarian failure.
• Small deletions of the long arm of the X-chromosome distal to Xq24 are not included in the diagnosis of Turner syndrome. ^[3]

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