johnson–mcmillin syndrome johnson–mcmillin syndrome johnson–mcmillin syndrome, also known as johnson neuroectodermal syndrome, is a neuroectodermal syndrome characterized by conductive hearing loss and alopecia, microtia, conductive hearing loss, anosmia/hyposmia, and hypogonadotropic hypogonadism. johnson–mcmillin syndromeother namesjohnson neuroectodermal syndrome, alopecia–anosmia–deafness–hypogonadism syndromejohnson–mcmillin syndrome is inherited in an autosomal dominant manner.