Seronegative Myasthenia Gravis, as a Rare Autoimmune Condition in Turner Syndrome

Table 2

Clinical characteristics of our patient compared to the first reported case of TS affected with MG.

Clinical characteristics	Our index case	First published case^1 (Chen et al., 1978) [17]
Age at MG onset	6 years	15 years
Age of TS diagnosis	10 years	10 years
Ethnicity	African American	Caucasian
Genetic defects (TS karyotype)	45,X/46,X,i(X)(q10)	45,X/46,XX
MG symptoms	Left eye ptosis (+), ophthalmoplegia (−)	Bilateral ptosis (+), ophthalmoplegia (+)
	Frequent fall (+), fatigue (+)	Frequent fall (+), fatigue (+)
Serology	Negative AChR, MuSK, and α-SM Abs	AChR Abs and MuSK not performed. Negative α-SM Abs
Tensilon test and EMG	Positive	Positive
Thyroid autoimmunity	α-TPO (+) and α-Tg (+)	α-TPO (+) and α-Tg (+)
	Euthyroid up to this point	Developed hypothyroid at the age of 15 y
Other antibody screening	Positive: α-GAD-65	Positive: ASMA, α-myelin Ab
	Negative: AGA, ASMA, α-SM Ab, ANA, α-dsDNA, α-ssDNA, α-MPO, proteinase-3, α-adrenal Abs, direct α-globulin Abs	Negative: α-DNA Ab, α-adrenal Ab, α-Coomb^2 Ab
Initial treatment	Cholinesterase inhibitors and glucocorticoid with no response	Cholinesterase inhibitors with no response
Definitive treatment	Periodic IVIG infusion	Thymectomy followed by cholinesterase inhibitors

EMG: electromyography; AChR-Abs: acetylcholine receptor antibodies; α-TPO: anti-thyroperoxidase; α-Tg: anti-thyroglobulin; α-GAD-65: anti-glutamic acid decarboxylase-65; ASMA: anti-smooth muscle antibodies; α-SM Ab: anti-striated muscle antibodies; ANA: antinuclear antibodies; MPO: myeloperoxidase; AGA: anti-gliadin antibodies. ¹All the information in the 3rd column was obtained from the first published case for comparison purpose. ²Direct antiglobulin Ab test (direct Coomb test) was done to evaluate for hemolytic anemia. Chen et al. did not mention which antibodies were tested.