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3M syndrome is a rare disorder that involves the gene cullin-7 (CUL7). CUL7 modulates odour detection, conditions the olfactory response (OR) and plays a role in the development of the olfactory system. Despite this involvement, there are no direct studies on olfactory functional effects in 3M syndrome. The purpose of the present work was to analyse the cortical OR through chemosensory event-related potentials (CSERPs) and power spectra calculated by electroencephalogram (EEG) signals recorded in 3M infants: two twins (3M-N) and an additional subject (3M-O). The results suggest that olfactory processing is diversified. Comparison of N1 and Late Positive Component (LPC) indicated substantial differences in 3M syndrome that may be a consequence of a modified olfactory processing pattern. Moreover, the presence of delta rhythms in 3M-O and 3M-N clearly indicates their involvement with OR, since the delta rhythm is closely connected to chemosensory perception, in particular to olfactory perception.

3M syndrome is a rare autosomal recessive dwarfism syndrome. The distinctive features of this syndrome are related to a limitation of prenatal growth, facial dysmorphism, the absence of microcephaly and absence of mental impairment. The subjects affected by this form of disorder often have respiratory problems and present different facial morphology (i.e., fleshy nose, antero-verse nostrils) [1]. The aim of this research was to investigate how the 3-M syndrome could have implications in the olfactory system. No study has so far been conducted on 3M to evaluate the use of olfactory event related potentials (OERP) as tools for investigating the functional response to chemical stimulation. Materials and Methods 3 male siblings, diagnosed as 3M syndrome, [2 newborns twins of 4 months old (3M-N) and a 3M 18 months old (3M-O)], were compared with two controls couple of twins (HS), matched by age and sex. The subjects performed an olfactory recognition task. The scent was administered through the device US2017127971 (A1) [2], with 20 μL of Eucalyptus. The paradigm of presentation corresponds to the stimulation of OERP. The analysis considered the olfactory components N1 and LPC [3], the wavelet and the connectivity values. Results The subject 3M-O shows, on N1, greater amplitudes (average amplitude 3M V -45 vs HS V -25) e delayed latencies (average latency 3M 440 ms. vs HS 200 ms) and on LPC greater amplitudes (3M-O V +17,5 vs HS V +5) and faster latencies (3M-O 260 ms vs HS 380 ms). The LPC data concern the response obtained in the right fronto-lateral area. Through the brain mapping it appears that the 3M-O subject shows a greater left lateralization. The 3M-N twins show, on both N1 and LPC, smaller amplitudes (N1: 3M-NV-17,5 vs HS V18,5; LPC: 3M-N V10 vs HS V 22,50) and delayed latencies (N1:3M-N 350 ms. vs HS 225 ms; LPC: 3M-N 220 ms vs HS 340 ms). Within the range between 70ms - 250ms, there is almost minimal activation of the parietal area in the case of 3M-N twins. In the range between 250ms to 420ms, 3M-N and 3M-O subjects showed an activation of part of the left hemisphere, of the parietal and of the left occipital area; while the HS showed an activation of parietal, left frontotemporal and right occipital areas. The wavelet analysis shows greater connectivity in alpha and delta in the case of the subject 3M-O and 3M-N vs HS. Conclusions In 3M syndrome, the olfactory processing seems to be clearly diversified (see Fig.1). In particular, the differences in the N1 and LPC components indicate substantial differences in 3M syndrome that can modify the pattern of olfactory processing. Moreover, the 3M subjects, in addition to greater connectivity, show different localizations of arousal due to olfactory stimulation, highlighting the implication of much larger areas ranging from the left hemisphere to the right hemisphere including occipital localizations.

The olfactory system is extremely connected to the gustatory system, and at an evolutionary level, the appetite stimulation is elicited by drivers connected to cross-modal and multisensory trigger. The most recent technological tools now allow both to reconstruct in the laboratory sophisticated odors, and to administer the same smells through olfactometers interfaced with neuroimaging instruments. The purpose of this presentation will be to illustrate, through a neurodevelopmental approach, several studies carried out to evaluate both Olfactory Event Related Potentials and gamma variation to olfactory responses, presenting odorous stimuli with edible and non-edible characteristics and associating these parameters with metabolic (i.e, Body Mass Index and neuroendocrine regulators) and dietary characteristics of the subjects, to evaluate how the olfactory guided behaviour can exist. Data will be presented regarding studies conducted with a new patented olfactory device, the US2017127971 (A1), on Obstructive Sleep Apnea Subjects, Mild Cognitive Impairment, healthy adults and newborns and newborns the 3 M syndrome (a rare disease).