Patients with CHARGE association: a model to study saccular function in the human.

The term CHARGE association refers to a combination of congenital malformations, the mnemonic CHARGE designating the most frequently occurring anomalies in the constellation. "C" indicates coloboma of the retina, "H" heart defects, "A" choanal atresia, "R" retarded growth and/or central nervous system anomalies, "G" genital hypoplasia, and "E" ear anomalies and/or deafness. The inner ear anomaly consists of a specific form of labyrinthine dysplasia that includes Mondini dysplasia of the pars inferior (cochlea and saccule) and complete absence of the pars superior (utricle and semicircular canals). We observed the development of a child with CHARGE association up to the age of 10 years. There was complete absence of nystagmic response to bithermal caloric and rotatory pendular stimuli. A nystagmic reaction was elicited by the off-vertical axis rotation test, indicating stimulation of the saccular macula, the sole remaining vestibular sense organ in this dysplasia. This reaffirms that the saccule is a vestibular organ, even though it is located in the pars inferior. In spite of the severe bilateral vestibular deficit and coloboma of the retina, the child was able to walk at the age of 2 years. The delay in the development of walking was not due to central nervous system anomalies, as suggested by the "R" of the acronym CHARGE, but rather, to the severe sensorineural visual and vestibular deficits.