Nakalanga syndrome: Clinical characteristics, potential causes, and its relationship with recently described Nodding syndrome

21.11.2019 | All others

A patient with Nakalanga syndrome (NLS) is unlikely to present for clinical care in Europe because cases are confined to impoverished sub-Saharan communities. Most western neurologists have never heard of NLS although its close neighbor Nodding syndrome (NS) is now entering the lexicon. These closely related disorders, perhaps clinical phenotypes of the same disease process, impact undernourished children who have short lifespans. Signs common to both NS and NLS include: growth attenuation, with dwarfism pathognomic in NLS and rare in NS; perturbation of reproductive system development, with delayed onset of secondary sex characteristics; seizures, including vertical head nodding in NS that is preceded, accompanied or followed by various epileptic phenomena that advance with time; cognitive deficits expressed as mental retardation (NLS) and advancing dementia sometimes attended by clinical evidence of motor weakness and parkinsonism (NS); and widespread cerebral (notably frontal) and cerebellar atrophy. associated with tauopathy that emphasizes the frontal cortex (NS). While NS appears to be a unique progressive epileptiform neurodegenerative disease, NLS is unstudied with respect to neurological course, brain imaging, electroencephalography and neuropathology. On the other hand, while available evidence in NLS points to a hypothalamic-pituitary disorder, only one study is suggestive of neuroendocrine perturbation in NS. Binding the two disorders is a very strong association with Onchocerca volvulus (OV) infection, including the common sub-Saharan distribution of onchocerciasis and NS+NLS, the disappearance of NLS in West Uganda after DDT-mediated eradication of the OV vector (Simulium spp.), and the higher rates of OV infestation of NS cases vs. controls. While OV has been held directly responsible for many cases of NS, NLS and epilepsy in the sub-Sahara, this important paper emphasizes that a cause-effect relationship has not been established. Whatever the explanation, study of NLS and NS promises to illuminate the etiology of epilepsy, neuroendocrine disorders, and neurodegenerative disease.

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