Monoallelic intragenic POU3F2 variants lead to neurodevelopmental delay and hyperphagic obesity, confirming the gene's candidacy in 6q16.1 deletions

While common obesity accounts for an increasing global health burden, its monogenic forms have taught us underlying mechanisms via more than 20 single-gene disorders. Among these, the most common mechanism is central nervous system dysregulation of food intake and satiety, often accompanied by neurodevelopmental delay (NDD) and autism spectrum disorder. In a family with syndromic obesity, we identified a monoallelic truncating variant in POU3F2 (alias BRN2) encoding a neural transcription factor, which has previously been suggested as a driver of obesity and NDD in individuals with the 6q16.1 deletion. In an international collaboration, we identified ultra-rare truncating and missense variants in another ten individuals sharing autism spectrum disorder, NDD, and adolescent-onset obesity. Affected individuals presented with low-to-normal birth weight and infantile feeding difficulties but developed insulin resistance and hyperphagia during childhood. Except for a variant leading to early truncation of the protein, identified variants showed adequate nuclear translocation but overall disturbed DNA-binding ability and promotor activation. In a cohort with common non-syndromic obesity, we independently observed a negative correlation of POU3F2 gene expression with BMI, suggesting a role beyond monogenic obesity. In summary, we propose deleterious intragenic variants of POU3F2 to cause transcriptional dysregulation associated with hyperphagic obesity of adolescent onset with variable NDD.

Perinatal, metabolic, and reproductive features in PPARG-related lipodystrophy

OBJECTIVE

The adipogenic PPARG-encoded PPARγ nuclear receptor also displays essential placental functions. We evaluated the metabolic, reproductive, and perinatal features of patients with PPARG-related lipodystrophy.

METHODS

Current and retrospective data were collected in patients referred to a National Rare Diseases Reference Centre.

RESULTS

26 patients from 15 unrelated families were studied (18 women, median age 43 years). They carried monoallelic PPARG variants except a homozygous patient with congenital generalized lipodystrophy. Among heterozygous patients aged 16 or more (n = 24), 92% had diabetes, 96% partial lipodystrophy (median age at diagnosis 24 and 37 years), 78% hypertriglyceridaemia, 71% liver steatosis, and 58% hypertension. The mean BMI was 26 ± 5.0 kg/m2. Women (n = 16) were frequently affected by acute pancreatitis (n = 6) and/or polycystic ovary syndrome (n = 12). Eleven women obtained one or several pregnancies, all complicated by diabetes (n = 8), hypertension (n = 4), and/or hypertriglyceridaemia (n = 10). We analysed perinatal data of patients according to the presence (n = 8) or absence (n = 9) of a maternal dysmetabolic environment. The median gestational age at birth was low in both groups (37 and 36 weeks of amenorrhea, respectively). As expected, the birth weight was higher in patients exposed to a foetal dysmetabolic environment of maternal origin. In contrast, 85.7% of non-exposed patients, in whom the variant is, or is very likely to be, paternally-inherited, were small for gestational age.

CONCLUSIONS

Lipodystrophy-related PPARG variants induce early metabolic complications. Our results suggest that placental expression of PPARG pathogenic variants carried by affected foetuses could impair prenatal growth and parturition. This justifies careful pregnancy monitoring in affected families.

Excess of de novo variants in genes involved in chromatin remodelling in patients with marfanoid habitus and intellectual disability

PURPOSE

Marfanoid habitus (MH) combined with intellectual disability (ID) (MHID) is a clinically and genetically heterogeneous presentation. The combination of array CGH and targeted sequencing of genes responsible for Marfan or Lujan-Fryns syndrome explain no more than 20% of subjects.

METHODS

To further decipher the genetic basis of MHID, we performed exome sequencing on a combination of trio-based (33 subjects) or single probands (31 subjects), of which 61 were sporadic.

RESULTS

We identified eight genes with de novo variants (DNVs) in at least two unrelated individuals (ARID1B, ATP1A1, DLG4, EHMT1, NFIX, NSD1, NUP205 and ZEB2). Using simulation models, we showed that five genes (DLG4, NFIX, EHMT1, ZEB2 and ATP1A1) met conservative Bonferroni genomewide significance for an excess of the observed de novo point variants. Overall, at least one pathogenic or likely pathogenic variant was identified in 54.7% of subjects (35/64). These variants fell within 27 genes previously associated with Mendelian disorders, including NSD1 and NFIX, which are known to be mutated in overgrowth syndromes.

CONCLUSION

We demonstrated that DNVs were enriched in chromatin remodelling (p=2×10^-4) and genes regulated by the fragile X mental retardation protein (p=3×10^-8), highlighting overlapping genetic mechanisms between MHID and related neurodevelopmental disorders.

Identification of a novel mutation confirms the implication of IFT172 (BBS20) in Bardet-Biedl syndrome

Bardet-Biedl syndrome (BBS; MIM 209900) is a recessive heterogeneous ciliopathy characterized by retinitis pigmentosa (RP), postaxial polydactyly, obesity, hypogonadism, cognitive impairment and kidney dysfunction. So far, 20 BBS genes have been identified, with the last reported ones being found in one or very few families. Whole-exome sequencing was performed in a consanguineous family in which two affected children presented typical BBS features (retinitis pigmentosa, postaxial polydactyly, obesity, hypogonadism and cognitive impairment) without any mutation identified in known BBS genes at the time of the study. We identified a homozygous splice-site mutation (NM_015662.2: c.4428+3A>G) in both affected siblings in the last reported BBS gene, namely, Intraflagellar Transport 172 Homolog (IFT172). Familial mutation segregation was consistent with autosomal recessive inheritance. IFT172 mutations were initially reported in Jeune and Mainzer-Saldino syndromes. Recently, mutations have also been found in isolated RP and Bardet-Biedl-like ciliopathy. This is the second report of IFT172 mutations in BBS patients validating IFT172 as the twentieth BBS gene (BBS20). Moreover, another IFT gene, IFT27, was already associated with BBS, confirming the implication of IFT genes in the pathogenesis of BBS.

Newly diagnosed rheumatic heart disease among indigenous populations in the Pacific

OBJECTIVES

Rheumatic heart disease (RHD) remains the leading acquired heart disease in the young worldwide. We aimed at assessing outcomes and influencing factors in the contemporary era.

METHODS

Hospital-based cohort in a high-income island nation where RHD remains endemic and the population is captive. All patients admitted with newly diagnosed RHD according to World Heart Federation echocardiographic criteria were enrolled (2005-2013). The incidence of major cardiovascular events (MACEs) including heart failure, peripheral embolism, stroke, heart valve intervention and cardiovascular death was calculated, and their determinants identified.

RESULTS

Of the 396 patients, 43.9% were male with median age 18 years (IQR 10-40)). 127 (32.1%) patients presented with mild, 131 (33.1%) with moderate and 138 (34.8%) with severe heart valve disease. 205 (51.8%) had features of acute rheumatic fever. 106 (26.8%) presented with at least one MACE. Among the remaining 290 patients, after a median follow-up period of 4.08 (95% CI 1.84 to 6.84) years, 7 patients (2.4%) died and 62 (21.4%) had a first MACE. The annual incidence of first MACE and of heart failure were 59.05‰ (95% CI 44.35 to 73.75) and 29.06‰ (95% CI 19.29 to 38.82), respectively. The severity of RHD at diagnosis (moderate vs mild HR 3.39 (0.95 to 12.12); severe vs mild RHD HR 10.81 (3.11 to 37.62), p<0.001) and ongoing secondary prophylaxis at follow-up (HR 0.27 (0.12 to 0.63), p=0.01) were the two most influential factors associated with MACE.

CONCLUSIONS

Newly diagnosed RHD is associated with poor outcomes, mainly in patients with moderate or severe valve disease and no secondary prophylaxis.

Relationships Between Clinico-Epidemiological Patterns of Invasive Meningococcal Infections and Complement Deficiencies in French South Pacific Islands (New Caledonia)

PURPOSE

Invasive Meningococcal Disease (IMD) is three fold more common in New Caledonia (NC) than in metropolitan France and many IMD cases (35.7%) are due to Y and W135 serogroups. The purpose of our study was to identify IMD risk factors in NC.

METHODS

A retrospective study of all IMD cases that occurred in NC between 2005 and 2011 was conducted. Socio-environmental, clinical and biological data were collected. A search for immune deficiency was proposed to all cases. IMD presentation and outcome were compared according to meningoccal serogroups and the complement deficiency status (C-deficiency).

RESULTS

Sixty-six sporadic IMD cases (29 B serogroup, 20 Y or W135, 6 C, 1 A, 10 unknown) occurred in 64 patients often <24 years-old and of Melanesian origin. Five patients died (7.8%). No socio-environmental risk factors were identified. No asplenia, HIV infection or immunoglobulin deficiencies were found. Two patients had diabetes and 28 of 53 (52.8%) patients had C-deficiency including 20 (71.4%) cases of late complement component deficiency. Patients with C-deficiency were mainly Melanesian (92.8%) originating from the Loyalty Islands (62.1%). They were mostly infected with Y/W135 (42.9%) or B serogroups (32.1%). They often developed later and more severe disease than patients without C-deficiency (need for intensive cares in 60% versus 28.0% of cases, p = 0.01).

CONCLUSIONS

A high prevalence of C-deficiency in the Melanesian population may explain epidemiological and clinical features of IMD in NC. Our results imply an adaptation of meningococcal vaccine strategies in NC.

Association between age and severity to leptospirosis in children

Background

In endemic areas, leptospirosis is more common and more severe in adults compared with children. Reasons to explain this discrepancy remain unclear and limited data focusing on adolescents are available. The objective of the study was to describe disease spectrum and outcome differences in children and adolescents admitted for leptospirosis in a large at-risk population.

Methods

Clinical and laboratory data were obtained on hospitalized cases in New Caledonia from 2006 to 2012.

Results

Data of 60 patients <18 years of age (25 children under 14 and 35 adolescents aged 14 to 17) with confirmed leptospirosis were analyzed. Compared with children, adolescents presented more often with classic features of Weil disease (p = 0.02), combining hepatic and renal involvement with or without pulmonary participation. Jarisch-Herxheimer reactions were observed more often among adolescents (p<0.01). The overall case fatality rate was low (1 adolescent versus 0 children).

Conclusion

Severe leptospirosis in adolescents may be more likely to show adults' characteristics compared with children. Further studies are required to explore age-dependant host factors, including puberty-related physiological changes.

Leptospirosis is endemic in tropical areas and seems to affect adults more often and more severely than children. Factors responsible for such differences have not been clearly established. However, host-related factors are believed to play a role in the development of severe leptospirosis. The study aimed to describe disease spectrum and outcome differences in confirmed cases in children and adolescents in New Caledonia. One major finding is the milder presentation of children compared with adolescents. Clinical and biological characteristics in adolescents are similar to adults, including occurrence of Jarisch-Herxheimer reactions. Further studies are required to explore age-dependant host factors, including puberty-related physiological changes.

Systematic molecular and cytogenetic screening of 100 patients with marfanoid syndromes and intellectual disability

The association of marfanoid habitus (MH) and intellectual disability (ID) has been reported in the literature, with overlapping presentations and genetic heterogeneity. A hundred patients (71 males and 29 females) with a MH and ID were recruited. Custom-designed 244K array-CGH (Agilent®; Agilent Technologies Inc., Santa Clara, CA) and MED12, ZDHHC9, UPF3B, FBN1, TGFBR1 and TGFBR2 sequencing analyses were performed. Eighty patients could be classified as isolated MH and ID: 12 chromosomal imbalances, 1 FBN1 mutation and 1 possibly pathogenic MED12 mutation were found (17%). Twenty patients could be classified as ID with other extra-skeletal features of the Marfan syndrome (MFS) spectrum: 4 pathogenic FBN1 mutations and 4 chromosomal imbalances were found (2 patients with both FBN1 mutation and chromosomal rearrangement) (29%). These results suggest either that there are more loci with genes yet to be discovered or that MH can also be a relatively non-specific feature of patients with ID. The search for aortic complications is mandatory even if MH is associated with ID since FBN1 mutations or rearrangements were found in some patients. The excess of males is in favour of the involvement of other X-linked genes. Although it was impossible to make a diagnosis in 80% of patients, these results will improve genetic counselling in families.

[Leprosy with an unusual course]

In developed countries, Hansen disease, or leprosy, is a rare and little-known disease. Over the last few years, its prevalence in New Caledonia has remained stable (0.35 per 10,000 inhabitants). We report the case of an 11-year-old child who presented lepromatous leprosy complicated by a type 2 reaction. Despite appropriate treatment, the course was unusual with fever lasting a few weeks associated with asthenia, weight loss, and biological perturbations such as inflammatory syndrome, anemia, and hyperferritinemia. After a brief review of Hansen disease and its complications, we discuss the different hypotheses that can explain the clinical and biological progression of our patient (hemolytic anemia secondary to dapsone, type 2 reaction, and aspects of hemophagocytic syndrome) and describe therapeutic management, which led to a good outcome.

Lower respiratory infections among hospitalized children in New Caledonia: a pilot study for the Pneumonia Etiology Research for Child Health project

We conducted a prospective pilot study over a 1-year period in New Caledonia in preparation for the Pneumonia Research for Child Health (PERCH) project. The pathogens associated with hospitalized lower respiratory infections in children were identified through the use of culture of induced sputum and blood, urinary antigen detection, polymerase chain reaction (PCR) on respiratory specimens, and serology on paired sera. Respiratory viruses were detected on respiratory specimens by immunofluorescence and PCR, and by serology on paired sera. Pathogens were detected in 87.9% of the 108 hospitalized cases. Viruses represented 81.6% of the 152 pathogens detected. Respiratory syncytial virus and rhinovirus were the most frequent, accounting for 32.2% and 24.3% of the pathogens identified, respectively. Only 26.3% of 99 induced sputum specimens collected were determined to be of good quality, which may be a consequence of the collection method used.

[Tobacco and marijuana use in adolescent students in Noumea]

INTRODUCTION

New Caledonia is situated in the western South Pacific 20000 km from France. In this Overseas Territory (pays d'outre-mer [POM]) the prevalence of tobacco smoking is very high and estimated at 30% among men and 34% among women. Experimenting with cannabis is also very widespread. The incidence of chronic respiratory illness and lung cancer remains high in the Territory. Modern laws protecting non-smokers still do not exist. This study aims at describing the behaviour of young people from 14 to 18 years old, at school in the public sector of Noumea, with respect to tobacco and marijuana consumption. This survey examines the way this behaviour varies according to age, sex, community, place of residence and socioeconomic conditions, in order to identify the most exposed groups. Finally, we study the effect of this consumption on the respiratory health of young school people.

METHODS

The enquiry was undertaken from May 4th to 15th 2009 in 16 classes drawn randomly from the colleges and secondary schools of Noumea (439 pupils). The survey consisted of an anonymous questionnaire containing 48 questions grouped into five subjects: a sociodemographic description of the subject and his/her family, the family lifestyle, tobacco consumption, marijuana consumption and a respiratory questionnaire. The completion of the questionnaires took, on average, 25 minutes and took place in class in the presence of the doctor undertaking the survey. The data were analysed with Ethnos-4 software. The analysis was made in two stages: a descriptive study after uni- and bivariate analysis and an analytical study to identify the risk factors of the addictive practices. The statistical tests used were Pearson's chi(2) test and the Hosmer-Lemeshow test for calculation of odds ratio.

RESULTS

The participation rate was 95.2% (n = 415). The sample was predominantly female (56.6%) and 31% of the pupils were less than 16 years old. The number of tobacco smokers was considerable at 41.1%, 27.3% were regular daily smokers including 38.5% who smoked more than six cigarettes a day. The results were dependent on sex (female predominence) but independent of ethnic origin and socioeconomic factors. The number of cannabis smokers was 48% among whom 32% were regular consumers. The daily smokers were uniquely boys and the custom was more frequent among the Melanesian population. Only 11% of the pupils were worried about their consumption and, among them, only the regular smokers were more at risk of bronchial infection.

CONCLUSIONS

In New Caledonia, tobacco consumption levels are higher than those in developed countries. We did not find a falling trend compared with previous data. The use of cannabis remains very widespread at an early age, with a male predominance for daily consumption. For both, these addictions the perception of the risk and the desire to stop are weak. The population studied is representative of teenagers in the public sector schools in Grand-Noumea but probably does not reflect the situation on the whole territory. The results obtained suggest the value of a study of the whole of New Caledonia, the eventual purpose being to guide the public health authorities towards policies that help the young people of the country.

Invasive serotype 1 Streptococcus pneumoniae outbreaks in the South Pacific from 2000 to 2007

In New Caledonia, Wallis and Futuna, and French Polynesia, an active surveillance system was established to monitor pneumococcal serotype prevalence between 2000 and 2007. The most prevalent serotype was serotype 1, which belonged to the major clonal complex sequence type 306 (ST306) and was responsible for invasive pneumococcal disease outbreaks.

Nanophthalmos in a Melanesian population

PURPOSE

To characterize the ophthalmic features and causes of visual loss in a cohort of Melanesians living in New Caledonia with nanophthalmos.

METHODS

In this observational study, axial length, visual acuity (VA), cycloplegic autorefraction were assessed and dilated fundus examination was performed. Visual impairment was defined as VA<6/12 in the better eye, hypermetropia as >+1.0 dioptre (D), astigmatism as >or=1.0 D and anisometropia as >or=1.0 D difference between both eyes. Unilateral amblyopia was defined as at least a two-line difference in VA between both eyes and bilateral amblyopia as VA<6/12 in both eyes which was not adequately explained by refractive error and macular folds.

RESULTS

Seventeen community-dwelling participants (aged 1.1-45.3 years) with short axial length (range from 16.1 to 21.6 mm) were identified. Of the 17 subjects, 14 were found to have crowded optic discs, three with papillomacular folds, three with a papillomacular band and three with macular radial folds. Further, all subjects demonstrated bilateral hypermetropia (range from +1.3 D to +15.1 D). A high proportion of subjects had astigmatism (12) and anisometropia (nine) in at least one eye. Visual impairment was found in nine subjects: five bilateral and four unilateral. Causes of visual impairment included amblyopia (seven), ametropia (seven) and macular folds (two). Amblyopia was attributed to several factors, including hypermetropia, anisometropia, astigmatism and esotropia.

CONCLUSIONS

In this sample of Melanesians with nanophthalmos, a spectrum of ophthalmic features that was consistent with intraocular crowding was found. Over half of the subjects were visually impaired, mostly due to amblyopia and ametropia. Further characterization of the underlying genetic cause of nanophthalmos in this cohort will be the focus of future studies.

[Perforated gastric ulcer in the child: a rare complication, a case report]

Perforated gastric ulcer is unusual in children. We report a case in a girl with an unexpected evolution.

CASE REPORT

A 13-year-old girl was admitted for abdominal pain. She had no particular personal history but her father had a perforated ulcer. On admission she was not painful, her abdomen was soft on palpation. The white blood cell count was 1.7 x 10(3)/mm3. A right pneumoperitoneum was seen on an abdominal X-ray film. Because of her good general status and the normalization of the abdominal X ray film six hours later, no surgical exploration was performed. On the fourth day, a gastrointestinal endoscopy showed an anterior gastric ulcer which was perforated. Biopsies did not isolate H. pylori. The patient was given a treatment with amoxicillin-metronidazole (7 d) and oméprazole (7 weeks). An endoscopic control, one month later, showed a total healing of the gastric ulcer.

CONCLUSION

Peptic ulcerations and their complications are underdiagnosed in childhood. This could lead to delay in diagnosis or inappropriate treatment specially in case of perforation.

Effect of early, short-term supplementation on weight and linear growth of 4-7-mo-old infants in developing countries: a four-country randomized trial

The effect of supplementation on growth was tested by means of four similar controlled randomized trials in the Congo (n = 120), Senegal (n = 110), Bolivia (n = 127), and New Caledonia (n = 90). Four-month-old infants were randomly allocated to supplement or control groups. A cereal-based precooked porridge was offered twice daily for 3 mo and consumption was monitored. Both groups were free to eat local food. At 7 mo of age, all infants were still breast-fed in the Congo, Senegal, and Bolivia compared with 47% in New Caledonia. Mean daily consumption of the supplement varied among countries (558-790 kJ/d). Mean length at 4 mo was lowest in Bolivia, higher in Senegal and the Congo, and near the National Center for Health Statistics reference in New Caledonia. The mean 4-7 mo length increment was 0.48 cm higher for supplemented than for control infants in Senegal (P < 0.05), whereas weight increments did not differ. No significant effect was found in the other countries.