Intragenic FMR1 disease-causing variants: a significant mutational mechanism leading to Fragile-X syndrome.

Fragile-X syndrome (FXS) is a frequent genetic form of intellectual disability (ID). The main recurrent mutagenic mechanism causing FXS is the expansion of a CGG repeat sequence in the 5'-UTR of the FMR1 gene, therefore, routinely tested in ID patients. We report here three FMR1 intragenic pathogenic variants not affecting this sequence, identified using high-throughput sequencing (HTS): a previously reported hemizygous deletion encompassing the last exon of FMR1, too small to be detected by array-CGH and inducing decreased expression of a truncated form of FMRP protein, in three brothers with ID (family 1) and two splice variants in boys with sporadic ID: a de novo variant c.990+1G>A (family 2) and a maternally inherited c.420-8A>G variant (family 3). After clinical reevaluation, the five patients presented features consistent with FXS (mean Hagerman's scores=15). We conducted a systematic review of all rare non-synonymous variants previously reported in FMR1 in ID patients and showed that six of them are convincing pathogenic variants. This study suggests that intragenic FMR1 variants, although much less frequent than CGG expansions, are a significant mutational mechanism leading to FXS and demonstrates the interest of HTS approaches to detect them in ID patients with a negative standard work-up.

Transcranial Magnetic Stimulation Combined With Nicotine Replacement Therapy for Smoking Cessation: A Randomized Controlled Trial.

BACKGROUND: Further evidence suggests that repetitive Transcranial Magnetic Stimulation (rTMS) is an effective method to reduce tobacco craving among smokers. HYPOTHESIS: As relapse is common within a few days after smoking cessation, we hypothesized that combining the anti-craving effects of rTMS with Nicotine replacement therapy (NRT) to attenuate withdrawal symptoms could increase abstinence rates in smokers with severe nicotine dependence who quit smoking. METHODS: Thirty-seven smokers who failed to quit with the usual treatments were randomly assigned to two treatment groups to receive either active (n = 18) or sham (n = 19) 1-Hz rTMS of the right dorsolateral prefrontal cortex. The day after quitting smoking, each patient combined NRT (21-mg patch) with active or sham rTMS (10 sessions) for 2 weeks. Cessation support was then continued with NRT alone using lower-dose patches. Abstinence rates and self-report craving scales were used to assess the therapeutic results during the combined treatment and for up to 12 weeks after quitting. RESULTS: At the end of the combined treatment, there were significantly more abstinent participants in the active rTMS group (n = 16) than in the sham rTMS group (n = 9) (P = 0.027). The craving scales analysis revealed that active rTMS (P = 0.011) but not sham rTMS (P = 0.116) led to a significant decrease in the compulsive factor. However, no lasting rTMS effect was found. CONCLUSIONS: 1-Hz rTMS combined with NRT improved the success rate of abstinence in smokers during tobacco cessation. The stimulation-induced reduction in compulsivity may explain this result.

20 ans après: a second mutation in MAOA identified by targeted high-throughput sequencing in a family with altered behavior and cognition.

Intellectual disability (ID) is characterized by an extraordinary genetic heterogeneity, with >250 genes that have been implicated in monogenic forms of ID. Because this complexity precluded systematic testing for mutations and because clinical features are often non-specific, for some of these genes only few cases or families have been unambiguously documented. It is the case of the X-linked gene encoding monoamine oxidase A (MAOA), for which only one nonsense mutation has been identified in Brunner syndrome, characterized in a single family by mild non-dysmorphic ID and impulsive, violent and aggressive behaviors. We have performed targeted high-throughput sequencing of 220 genes, including MAOA, in patients with undiagnosed ID. We identified a c.797_798delinsTT (p.C266F) missense mutation in MAOA in a boy with autism spectrum disorder, attention deficit and autoaggressive behavior. Two maternal uncles carry the mutation and have severe ID, with a history of maltreatment in early childhood. This novel missense mutation decreases MAOA enzymatic activity, leading to abnormal levels of urinary monoamines. The identification of this new point mutation confirms, for the first time since 1993, the monogenic implication of the MAOA gene in ID of various degrees, autism and behavioral disturbances. The variable expressivity of the mutation observed in male patients of this family may involve gene-environment interactions, and the identification of a perturbation in monoamine metabolism should be taken into account when prescribing psychoactive drugs in such patients.

3q27.3 microdeletional syndrome: a recognisable clinical entity associating dysmorphic features, marfanoid habitus, intellectual disability and psychosis with mood disorder.

BACKGROUND: Since the advent of array-CGH, numerous new microdeletional syndromes have been delineated while others remain to be described. Although 3q29 subtelomeric deletion is a well-described syndrome, there is no report on 3q interstitial deletions. METHODS: We report for the first time seven patients with interstitial deletions at the 3q27.3q28 locus gathered through the Decipher database, and suggest this locus as a new microdeletional syndrome. RESULTS: The patients shared a recognisable facial dysmorphism and marfanoid habitus, associated with psychosis and mild to severe intellectual disability (ID). Most of the patients had no delay in gross psychomotor acquisition, but had severe impaired communicative and adaptive skills. Two small regions of overlap were defined. The first one, located on the 3q27.3 locus and common to all patients, was associated with psychotic troubles and mood disorders as well as recognisable facial dysmorphism. This region comprised several candidate genes including SST, considered a candidate for the neuropsychiatric findings because of its implication in interneuronal migration and differentiation processes. A familial case with a smaller deletion allowed us to define a second region of overlap at the 3q27.3q28 locus for marfanoid habitus and severe ID. Indeed, the common morphological findings in the first four patients included skeletal features from the marfanoid spectrum: scoliosis (4/4), long and thin habitus with leanness (average Body Mass Index of 15 (18.5