Hi, I M Dr.Kumarbhargav I understood your problem Klippel-feil syndrome is shortness of neck due to either reduction in the number of cervical vertebrae or fusion of hemivertebrae, As it is frequently associated with other anomalies like scoliosis. The thyroid gland may have mal positioned at abnormal location, so can not be indicated on routine ultrasound and radiology. So positioning at abnormal location must be the reason for such incidence. Thanks for contacting health care magic, Ask if you want more details. Take care.