Association Between Incomplete Partition Type III and Abnormal Hypothalamic Morphology: Further Imaging Evidence

Abstract

Incomplete partition III (IP-III), characterized by congenital mixed or sensorineural hearing loss, is a rare genetic disease transmitted through X-linked mode of inheritance. Inner ear findings of IP-III have been well described and allow an immediate diagnosis to be made. Recently, an association between IP-III and distinct hypothalamic malformations has been reported in some of the patients with IP-III. The purpose of this study was to investigate the morphologic abnormalities of the hypothalamus in IP-III. Magnetic resonance imaging studies of 8 subjects, including 1 set of brothers, who were diagnosed with IP-III based on their clinical and inner ear imaging findings, were analyzed. Of the 8 subjects, 7 demonstrated some degree of morphologic abnormality of the hypothalamus. Of these, 2 showed asymmetrical thickening, 1 showed symmetrical thickening, and 4 showed mass-like enlargement of the hypothalamus. Six of 7 subjects with hypothalamic abnormalities showed asymmetry in caudal extension of the abnormalities, which was more discernible on coronal oblique T2-weighted images. Clinically, none of the subjects had endocrinologic or neurologic symptoms. This retrospective analysis presents further magnetic resonance imaging evidence on the association between the rare IP-III malformations and the presence of hypothalamic morphologic abnormalities.