Tolerance and efficacy of sodium oxybate in childhood narcolepsy with cataplexy: a retrospective study

Narcolepsy with cataplexy is a sleep disorder characterized by excessive daytime sleepiness, irresistible sleep episodes, and sudden loss of muscle tone (cataplexy) mostly triggered by emotions. Narcolepsy with cataplexy is a disabling lifelong disorder frequently arising during childhood. Pediatric narcolepsy often results in severe learning and social impairment. Improving awareness about this condition increases early diagnosis and may allow patients to rapidly access adequate treatments, including pharmacotherapy and/or non-medication-based approaches. Even though children currently undergo pharmacotherapy, data about safety and efficacy in the pediatric population are scarce. Lacking international guidelines as well as drugs registered for childhood narcolepsy with cataplexy, physicians have no other alternative but to prescribe in an off-label manner medications identical to those recommended for adults. We retrospectively evaluated 27 children ranging from 6 to 16 years old, suffering from narcolepsy with cataplexy, who had been treated with off-label sodium oxybate and had been followed in a clinical setting. Throughout a semi-structured interview, we documented the good efficacy and tolerability of sodium oxybate in the majority of the patients. This study constitutes a preliminary step towards a further randomized controlled trial in childhood narcolepsy with cataplexy.

Strategies to work with HLA data in human populations for histocompatibility, clinical transplantation, epidemiology and population genetics: HLA-NET methodological recommendations

HLA-NET (a European COST Action) aims at networking researchers working in bone marrow transplantation, epidemiology and population genetics to improve the molecular characterization of the HLA genetic diversity of human populations, with an expected strong impact on both public health and fundamental research. Such improvements involve finding consensual strategies to characterize human populations and samples and report HLA molecular typings and ambiguities; proposing user-friendly access to databases and computer tools and defining minimal requirements related to ethical aspects. The overall outcome is the provision of population genetic characterizations and comparisons in a standard way by all interested laboratories. This article reports the recommendations of four working groups (WG1-4) of the HLA-NET network at the mid-term of its activities. WG1 (Population definitions and sampling strategies for population genetics’ analyses) recommends avoiding outdated racial classifications and population names (e.g. ‘Caucasian’) and using instead geographic and/or cultural (e.g. linguistic) criteria to describe human populations (e.g. ‘pan-European’). A standard ‘HLA-NET POPULATION DATA QUESTIONNAIRE’ has been finalized and is available for the whole HLA community. WG2 (HLA typing standards for population genetics analyses) recommends retaining maximal information when reporting HLA typing results. Rather than using the National Marrow Donor Program coding system, all ambiguities should be provided by listing all allele pairs required to explain each genotype, according to the formats proposed in ‘HLA-NET GUIDELINES FOR REPORTING HLA TYPINGS’. The group also suggests taking into account a preliminary list of alleles defined by polymorphisms outside the peptide-binding sites that may affect population genetic statistics because of significant frequencies. WG3 (Bioinformatic strategies for HLA population data storage and analysis) recommends the use of programs capable of dealing with ambiguous data, such as the ‘gene[rate]’ computer tools to estimate frequencies, test for Hardy–Weinberg equilibrium and selective neutrality on data containing any number and kind of ambiguities. WG4 (Ethical issues) proposes to adopt thorough general principles for any HLA population study to ensure that it conforms to (inter)national legislation or recommendations/guidelines. All HLA-NET guidelines and tools are available through its website http://hla-net.eu.

Motor events during REM sleep in patients with narcolepsy-cataplexy: a video-polysomnographic pilot study

OBJECTIVE

We carried out a systematic video-polysomnographic analysis of the number and type of motor events during REM sleep in narcolepsy-cataplexy patients with REM sleep behavior disorder (NC + RBD) but not clinical RBD (NC-RBD).

METHODS

Twelve NC + RBD and 10 NC-RBD male patients underwent video-polysomnography (video-PSG). Motor events of different type and complexity (i.e., elementary and complex movements and vocalizations) occurring during REM sleep were visually assessed, and indices of their frequency per hour of REM sleep were calculated. Subsequently, the index values were compared in NC + RBD versus NC-RBD patients.

RESULTS

Typical RBD behaviors observed in five NC + RBD patients were not included in any type of motor events. No objective conventional sleep parameter, including visual analysis of chin electromyographic (EMG) activity, significantly differed between the two groups of NC patients. NC + RBD patients showed higher occurrence of elementary movements (p = 0.034) during REM sleep compared with NC-RBD patients, but the occurrence of complex movements did not differ significantly.

CONCLUSIONS

Video-analysis of motor events during REM sleep may improve the diagnosis of RBD in NC. RBD in NC patients is mainly characterized by elementary rather than complex movements, consistent with the view that RBD with NC patients displays a distinct phenotype with respect to other RBD patients.

Description and molecular modeling of a novel human leukocyte antigen allele: A*32:22

We describe here the sequence and the molecular modeling of a new variant of HLA-A*32 allele officially named A*32:22. This novel allele has been detected in an Italian cord blood sample by sequence-based typing (SBT). The mutation (CAT →CGT), which has occurred at codon 151, at nucleotide position 524, implies an amino acidic change from Histidine to Arginine. Residue 151 is located on top of the molecule inside the region contacted by T cell receptor (TCR) and it is possibly involved in docking TCR. A positively charged residue is maintained on this position determining a slight change of electrostatic potential on the molecular surface. This suggests a limited functional relevance of the amino acid substitution encoded by A*32:22.

Mutations in DNMT1 cause autosomal dominant cerebellar ataxia, deafness and narcolepsy

Autosomal dominant cerebellar ataxia, deafness and narcolepsy (ADCA-DN) is characterized by late onset (30-40 years old) cerebellar ataxia, sensory neuronal deafness, narcolepsy-cataplexy and dementia. We performed exome sequencing in five individuals from three ADCA-DN kindreds and identified DNMT1 as the only gene with mutations found in all five affected individuals. Sanger sequencing confirmed the de novo mutation p.Ala570Val in one family, and showed co-segregation of p.Val606Phe and p.Ala570Val, with the ADCA-DN phenotype, in two other kindreds. An additional ADCA-DN kindred with a p.GLY605Ala mutation was subsequently identified. Narcolepsy and deafness were the first symptoms to appear in all pedigrees, followed by ataxia. DNMT1 is a widely expressed DNA methyltransferase maintaining methylation patterns in development, and mediating transcriptional repression by direct binding to HDAC2. It is also highly expressed in immune cells and required for the differentiation of CD4+ into T regulatory cells. Mutations in exon 20 of this gene were recently reported to cause hereditary sensory neuropathy with dementia and hearing loss (HSAN1). Our mutations are all located in exon 21 and in very close spatial proximity, suggesting distinct phenotypes depending on mutation location within this gene.

Description of the new allele HLA-DQB1*04:03:02

A new variant of HLA-DQB1*04:03 allele officially designated as HLA-DQB1*04:03:02 was detected in two unrelated Caucasoid individuals by polymerase chain reaction-sequence-specific primers and SBT. The new allele nucleotide sequence differs from HLA-DQB1*04:03:01 for a single silent point mutation in exon 2 at position 159, codon 21.

Narcolepsy with cataplexy associated with nocturnal compulsive behaviors: a case-control study

STUDY OBJECTIVES

To assess the prevalence of sleep related-eating disorder (SRED) and nocturnal smoking (NS) in patients with narcolepsy with cataplexy (NC).

DESIGN

Case-control study.

SETTING

University hospital.

PATIENTS OR PARTICIPANTS

65 consecutive adult NC patients (33 men; mean age 43.9 ± 19.2 years) and 65 age-, sex-, and geographical origin-matched controls.

INTERVENTIONS

Validated questionnaires were used to investigate SRED, NS, restless legs syndrome (RLS), and psychopathological traits (using Eating Disorder Inventory-2 [EDI-2]; Maudsley Obsessive-Compulsive Inventory [MOCI]; and Beck Depression Inventory [BDI]).

MEASUREMENTS AND RESULTS

NC patients showed a higher prevalence of SRED (32% vs 3%, P=0.00001), NS (21% vs 0%, P=0.00006), and RLS (18% vs 5%, P=0.013) than controls. Moreover, NC patients presented more frequently with an eating-related pathological profile on the EDI-2 (80% vs 46%, P=0.00006) and had a higher prevalence of depressed mood on the BDI (41% vs 18%, P=0.004). In comparison to patients without SRED, NC patients with SRED were more frequently women (71% vs 39%, P=0.013), had higher "bulimic" (29% vs 2%, P=0.004) and "social insecurity" (48% vs 18%, P=0.013) traits on the EDI-2, had higher obsessive-compulsiveness on the MOCI (29% vs 4%, P = 0.009), and were more depressed on the BDI (67% vs 29%, P=0.005). NC patients with NS showed more frequent pathological profiles on the EDI-2 (100% vs 75%, P=0.035), including the "bulimic" (29% vs 6%, P=0.015), "perfectionism" (43% vs 14%, P=0.016), and "social insecurity" (50% vs 22, P=0.035) profiles.

CONCLUSION

Our study shows a strong association of the compulsive nocturnal behaviors SRED and NS with adult NC.

Complex movement disorders at disease onset in childhood narcolepsy with cataplexy

Narcolepsy with cataplexy is characterized by daytime sleepiness, cataplexy (sudden loss of bilateral muscle tone triggered by emotions), sleep paralysis, hypnagogic hallucinations and disturbed nocturnal sleep. Narcolepsy with cataplexy is most often associated with human leucocyte antigen-DQB1*0602 and is caused by the loss of hypocretin-producing neurons in the hypothalamus of likely autoimmune aetiology. Noting that children with narcolepsy often display complex abnormal motor behaviours close to disease onset that do not meet the classical definition of cataplexy, we systematically analysed motor features in 39 children with narcolepsy with cataplexy in comparison with 25 age- and sex-matched healthy controls. We found that patients with narcolepsy with cataplexy displayed a complex array of ‘negative’ (hypotonia) and ‘active’ (ranging from perioral movements to dyskinetic–dystonic movements or stereotypies) motor disturbances. ‘Active’ and ‘negative’ motor scores correlated positively with the presence of hypotonic features at neurological examination and negatively with disease duration, whereas ‘negative’ motor scores also correlated negatively with age at disease onset. These observations suggest that paediatric narcolepsy with cataplexy often co-occurs with a complex movement disorder at disease onset, a phenomenon that may vanish later in the course of the disease. Further studies are warranted to assess clinical course and whether the associated movement disorder is also caused by hypocretin deficiency or by additional neurochemical abnormalities.

Heart transplantation with donor-specific antibodies directed toward denatured HLA-A*02:01: a case report

The development of solid-phase assays for antibody detection has aided in the frequent detection of human leukocyte antigen (HLA) antibodies in nonalloimmunized males. Some scientists have reported that these HLA antibodies are produced to pathogens or allergens and the reactivity with HLA coated beads is the result of cross-reactive epitopes. These antibodies may also be directed toward cryptic epitopes exposed on the denatured beads. In this report, we describe the case of a heart transplanted patient who exhibited anti-HLA-A*02:01 donor-specific antibodies detected with a bead-based assay (Luminex) and undetected with the complement-dependent cytotoxicity (CDC) test. Posttransplant monitoring, carried out with CDC and with Luminex on sera from this patient collected at the 2nd, 4th, 8th, and 12th posttransplant weeks and at 1 year confirmed the presence of anti-HLA-A*02:01 in all serum samples. Additional tests carried out with denatured and intact HLA molecules using single antigen beads demonstrated that the antibody was directed toward a cryptic epitope. One year after transplantation the patient is doing well. No sign of antibody-mediated rejection was observed throughout the follow-up. A comprehensive evaluation of the anamnesis and of antibodies is critical to avoid needless exclusion of organ donors.

Periodic leg movements during sleep in narcoleptic patients with or without restless legs syndrome

We compared periodic and non-periodic leg movements during sleep and polysomnography in patients with narcolepsy with cataplexy (NC) with or without restless legs syndrome (RLS) with matched idiopathic RLS (iRLS) and control subjects. We enrolled 100 patients with NC: 17 having RLS were compared with 34 sex- and age-matched patients without RLS and with 17 normal controls and 17 iRLS subjects. Periodic leg movements were highest in iRLS and lowest in controls, with those in NC with RLS very close to iRLS, but higher than those in NC without RLS. The periodicity indexes showed the highest value in iRLS followed by NC with or without RLS and, finally, by controls. The inter-leg movement intervals peaked between 10 and 50 s in NC with RLS and in iRLS, the former did not display the nocturnal gradual decrease of periodic leg movements typical of iRLS. Periodic leg movements during sleep and polysomnography displayed specific features in RLS and NC, respectively, with NC with RLS showing an intermediate pattern. Even if RLS is only detected by targeted interview in NC, its frequency and impact on night-time sleep architecture and continuity suggest that this condition should be routinely searched for in NC.

Analysis of the motivation for hematopoietic stem cell donation

The Italian Bone Marrow Donor Register is the institutional organization for management of unrelated hematopoietic stem cell donors. The law requires only a donor's clinical history, but not a psychosocial profile for registration. We have studied the donor's motivation for enlistment on the donor registry and the medical staff's need for this information to interact correctly with the donor. For this purpose we distributed a questionnaire to new donors at the 20 centers in the Lombardy Region over a period of 1 year. The analysis of the responses revealed a prevalence of extrinsic motivations that would not ensure continued registration for donation. Therefore, it is necessary that the donor be well informed and better educated about all aspects of donation, in order to produce a shift to an intrinsic motivation. This objective can be facilitated via professional training of health workers in communication.

Cut-off analysis of 19-cell Yb-doped double-cladding rod-type photonic crystal fibers

Yb-doped double-cladding large mode area rod-type photonic crystal fibers are a key component for power scaling in fiber laser systems. Recently, designs with 19-cell core defect, that is with 19 missing air-holes in the center of the photonic crystal cladding, have been proposed, with reported core diameter up to 100 μm. In this paper an analysis of the cut-off wavelength of the first high-order mode in such low-NA fibers is reported, accounting for different approaches for the definition of the cladding effective index. Results have shown that taking into account the finite fiber cross-section and considering the first cladding mode of the actual fiber is mandatory to obtain a correct estimate of the cut-off wavelength.