Johnson Neuroectodermal Syndrome

Clinical Features

Johnson et al. (1983) described a 'new' autosomal dominant neuroectodermal syndrome in which anosmia and hypogonadotropic hypogonadism were combined with conductive deafness, alopecia, and other anomalies. In 3 generations, 16 persons were affected. Deafness was associated with protruding ears, microtia, and/or atresia of the external auditory canal. There was an increased tendency to dental caries. Variable features included congenital heart defect, cleft palate, mild facial asymmetry, and mental retardation. The manifestations were explained on the basis of involvement of the ectoderm and neuroectoderm of the first 2 branchial arches, the Rathke pouch, and the diencephalon. There were several instances of male-to-male transmission. Johnston et al. (1987) reported a single patient in whom hypohidrosis was a conspicuous feature.

Hennekam and Holtus (1993) reported mother and son with facial nerve palsy, multiple truncal cafe-au-lait spots, and mild developmental delay. The mother also had hyposmia, increased tendency to caries and growth retardation; the son had hypotrichosis, hearing loss, and microtia. Bankier and Rose (1994) questioned the appropriateness of the diagnosis of the Johnson-McMillin syndrome in the family reported by Hennekam and Holtus (1993). They suggested that the manifestations in the mother and child fitted more in the oculoauriculovertebral spectrum (164210).

Schweitzer et al. (2003) described a female patient with features resembling those of previously reported cases of Johnson-McMillin syndrome. She was noted at birth to have multiple congenital anomalies including tetralogy of Fallot, microcephaly, total alopecia, cleft palate, micrognathia, bilateral microtia with canal atresia, preaxial polydactyly of the right hand, and a 2-vessel umbilical cord. The patient's mother had a history choanal stenosis and hyposmia, with total alopecia as an infant.

Inheritance

Male-to-male transmission in the family reported by Johnson et al. (1983) supports autosomal dominant inheritance.