TPO and ataxia telangiectasia: In polycystic ovary syndrome, we have demonstrated that the levels of 25(OH) vitamin D were significantly lower in women with Polycystic Ovary Syndrome (PCOS) and AT when compared to women with PCOS and without AT, although no correlation was found between 25(OH) vitamin D and anti-thyroid peroxidase antibodies (TPO-Ab), anti-thyroglobulin (TG-Ab) antibodies, free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) levels [12].