Indication for molecular testing by multiplex ligation-dependent probe amplification in parkinsonism

BACKGROUND

The monogenic forms of Parkinson's disease represent less than 10% of familial cases and a still lower frequency of sporadic cases. However, guidelines to orient genetic testing are lacking. We aim to establish the interest of multiplex ligation-dependent probe amplification as a primary screening test and to propose clinical criteria to guide genetic diagnostic tests for patients with suspected Mendelian Parkinson's disease.

METHODS

We recruited 567 patients with parkinsonism from 547 unrelated families and performed two multiplex ligation-dependent probe amplifications for each. We confirmed all pathogenic G2019S variants in the LRRK2 gene by Sanger sequencing and screened the PRKN gene for a second mutation in cases of one heterozygous structural variant in the PRKN gene.

RESULTS

The performance of multiplex ligation-dependent probe amplifications was 51/567 (9%) for the entire cohort and included 27 (4.8%) LRRK2 G2019S mutations, 19 (3.4%) PRKN mutations, and 5 (0.9%) SNCA locus duplications. The variables significantly associated with a positive test in the total cohort were North African ancestry (p < 0.0001), female sex (p = 0.004), and younger age at onset (p < 0.0008).

CONCLUSIONS

Retrospective analysis allowed us to refine our indication criteria: (i) North African ancestry, (ii) an age at onset < 40, or (iii) a familial history of parkinsonism with at least one affected first-degree relative. Our study highlights the interest of MLPA testing for other parkinsonisms cases with a family history, especially for patients with dementia with Lewy bodies or a multiple system atrophy-like phenotype.

Pd-based integrated optical hydrogen sensor on a silicon-on-insulator platform

We have experimentally demonstrated a compact, integrated optical hydrogen sensor on a silicon-on-insulator platform. The sensor consists of silicon waveguide coated with a thin palladium film. The sensitivity and response time of the sensor was tested for volumetric hydrogen concentrations ranging from 0% to 4%. The proposed hydrogen sensor shows great potential as a building block for an optical nose capable of simultaneous detection of multiple gases as well as environmental effects such as temperature and humidity.

Spontaneous internal carotid artery dissection with lower cranial nerve palsy

BACKGROUND

Typical presentation of spontaneous internal carotid artery (ICA) dissection is an ipsilateral pain in neck and face with Horner's syndrome and contralateral deficits. Although rare, lower cranial nerve palsy have been reported in association with an ipsilateral spontaneous ICA dissection.

CASE STUDIES

We report three new cases of ICA dissection with lower cranial nerve palsies.

RESULTS

The first symtom to appear was headache in all three patients. Examination disclosed a Horner's syndrome in two cases (1 and 2), an isolated XIIth nerve palsy in two patients (case 1 and 3) and IX, X, and XIIth nerve palsies (case 2) revealing an ipsilateral carotid dissection, confirmed by MRI and angiography. In all cases, prognosis was good after a few weeks.

CONCLUSIONS

These cases, analysed with those in the literature, led us to discuss two possible mechanisms: direct compression of cranial nerves by a subadventitial haematoma in the parapharyngeal space or ischemic palsy by compression of the ascending pharyngeal artery.

[Pseudomigraine with transient neurological signs and lymphocytic pleiocytosis]

We report the case of a 32-year-old man without previous medical history of migraine, who presented with severe headache and temporary focal neurological deficits. Lumbar puncture revealed aseptic lymphocytic pleiocytosis. The patient completly recovered within 2 months. This condition was suggestive of a transient syndrome of headache with neurologic deficits and CSF pleiocytosis. The main characteristics and the physiopathology of this uncommon disorder are discussed.