SAT-294 A Case of Turner Syndrome with Ambiguous Genitalia

Background: Turner syndrome is a common genetic condition caused by complete or partial absence of X chromosome. Often this condition is diagnosed prenatally. Neonates with this condition have variable presentations at birth, depending on the severity of genetic defect. Often these babies are born with cystic hygroma, facial dysmorphism, short stature and cardiac defects. They commonly present with normal female external and internal genitalia and may develop hypogonadism and streak ovaries later in life. We describe an unusual patient with prenatal diagnosis of Turner syndrome, who presented with palpable gonads and ambiguous genitalia at birth. Clinical case: Full term baby born with dysmorphic features suggestive of Turner syndrome. Prenatal testing raised suspicion for genetic defects. Amniocentesis confirmed 45X karyotype. Baby was born with cystic hygroma, bicuspid aortic valve, and congenital hypothyroidism. External genetalia were ambiguous with almost complete fusion of the labia, prominent clitoromegaly, severe hypospadias and palpable right gonad. Pelvic ultrasound failed to show any Mullerian structures. These findings raised the suspicion for mosiasm. Microarray and Blood karyotype with 50 cell count again revealed 45X karyotype. FISH analysis was negative for SRY gene and exhibited one signal for X chromosome only. Due to rising Testosterone and elevated 17-hydroxyprogesterone and anti-müllerian hormone, further testing was done. FISH analysis on fibroblast cultures was positive for SRY gene and confirmed 3/200 cells with 46XY karyotype. Male gender was assigned after mutual agreement between neonatologist, urologist, endocrinologist and parents. Gonadal biopsy and surgical correction is pending at the moment. Conclusion: The clinical phenotype of Mixed gonadal dysgenesis MGD with 45X/46XY karyotype is broad, with varying degree of genital ambiguity. The degree of genital ambiguity is not correlated with the presence and proportion of mosaic clones in different tissues. Our patient presented with somatic features of Turner syndrome, consistent with the karyotype identified in the blood. Genital ambiguity and lack of Mullerian ducts prompted further workup confirming MGD. A small number of patients with karyotype 45X/46XY can present with ambiguous genitalia and somatic features of Turner syndrome. Our case stresses out the importance of screening for a Y chromosome in cell lines other than blood in all Turner Syndrome patients and in patients with genital ambiguity.