Metacarpophalangeal pattern profile and bone age in Rett syndrome: further radiological clues to the diagnosis

Ultra-processed foods in a rural Ecuadorian community: associations with child anthropometry and bone maturation

Frequent ultra-processed food (UPF) consumption is consistently associated with poor health outcomes. Little is known about UPF intake during early childhood and its effects on growth. We assessed UPF in relation to child anthropometry, bone maturation, and their nutrition profiles in a rural Ecuadorian community. Covariate-adjusted regression models estimated relationships between UPF intake from a 24-hour Food Frequency Questionnaire and three outcomes: linear growth, weight status and bone maturation. Nutrient Profiling Models (NPM) evaluated a convenience sample of UPF (n 28) consumed by children in the community. In this cohort (n 125; mean age = 33·92 (sd 1·75) months), 92·8 % consumed some form of UPF the previous day. On average, children consuming UPF four to twelve times per day (highest tertile) had lower height-for-age z-scores than those with none or a single instance of UPF intake (lowest tertile) (β = -0·43 [se 0·18]; P = 0·02). Adjusted stunting odds were significantly higher in the highest tertile relative to the lowest tertile (OR: 3·07, 95 % CI 1·11, 9·09). Children in the highest tertile had significantly higher bone age z-scores (BAZ) on average compared with the lowest tertile (β = 0·58 [se 0·25]; P = 0·03). Intake of savoury UPF was negatively associated with weight-for-height z-scores (β = -0·30 [se 0·14]; P = 0·04) but positively associated with BAZ (β = 0·77 [se 0·23]; P < 0·001). NPM indicated the availability of unhealthy UPF to children, with excessive amounts of saturated fats, free sugars and sodium. Findings suggest that frequent UPF intake during early childhood may be linked to stunted growth (after controlling for bone age and additional covariates), despite paradoxical associations with bone maturation.

Altered Bone Status in Rett Syndrome

Rett syndrome (RTT) is a monogenic neurodevelopmental disorder primarily caused by mutations in X-linked MECP2 gene, encoding for methyl-CpG binding protein 2 (MeCP2), a multifaceted modulator of gene expression and chromatin organization. Based on the type of mutation, RTT patients exhibit a broad spectrum of clinical phenotypes with various degrees of severity. In addition, as a complex multisystem disease, RTT shows several clinical manifestations ranging from neurological to non-neurological symptoms. The most common non-neurological comorbidities include, among others, orthopedic complications, mainly scoliosis but also early osteopenia/osteoporosis and a high frequency of fractures. A characteristic low bone mineral density dependent on a slow rate of bone formation due to dysfunctional osteoblast activity rather than an increase in bone resorption is at the root of these complications. Evidence from human and animal studies supports the idea that MECP2 mutation could be associated with altered epigenetic regulation of bone-related factors and signaling pathways, including SFRP4/WNT/β-catenin axis and RANKL/RANK/OPG system. More research is needed to better understand the role of MeCP2 in bone homeostasis. Indeed, uncovering the molecular mechanisms underlying RTT bone problems could reveal new potential pharmacological targets for the treatment of these complications that adversely affect the quality of life of RTT patients for whom the only therapeutic approaches currently available include bisphosphonates, dietary supplements, and physical activity.

Teriparatide in the treatment of recurrent fractures in a Rett patient

Rett syndrome is a common X-linked neurodevelopmental disorder caused by mutations in the MECP2 gene. Patients with Rett syndrome have a low bone mineral density and increased risk of fracture. The present case report describes a successful novel therapeutic intervention with teriparatide with one patient with Rett syndrome, after suffering from recurrent low-trauma fractures at intervals of several years. Because of the severity of bone involvement, the decision was made to treat with teriparatide and subsequently with intravenous bisphosphonate. Since the initiation of the treatment, there was an evident improvement at densitometric and QUS parameters. Furthermore, until the present, no new fractures have appeared. This is the first report in which teriparatide was administered to a subjects with Rett syndrome. In conclusion, this report has shown the effectiveness of teriparatide in the management of osteoporotic fractures in one subjects with Rett syndrome. This report provides evidence that increased knowledge of bone pathology and fracture prevention in Rett subjects is important and should be addressed in future studies.

A comparative study of dual-X-ray absorptiometry and quantitative ultrasonography for the evaluating bone status in subjects with Rett syndrome

Rett syndrome, an X-linked neurodevelopmental disorder primarily affecting girls, is frequently characterized by a reduced bone mineral density (BMD) with an increased risk of fragility fractures. The aim of the study was to assess bone status by DXA technique and by quantitative ultrasound (QUS) in subjects with Rett syndrome and to evaluate which DXA or QUS parameters better correlate with clinical features. In 156 Rett subjects (mean age 13.6 ± 8.2 years) and in 62 controls, we measured BMD at femoral neck (BMD-FN) and at total femur (BMD-TF). Apparent volumetric bone mineral density (vBMAD) was also calculated. In all subjects, QUS parameters at phalanges by Bone Profiler-IGEA (amplitude-dependent speed of sound: AD-SoS and bone transmission time: BTT) were evaluated. We found that both DXA parameters and QUS parameters were significantly lower in Rett subjects than in controls. All clinical characteristics were positively correlated to BMD-FN, BMD-TF, AD-SoS, and BTT (p < 0.001) but not with vBMAD-FN. All ultrasonographic parameters were significantly correlated to BMD-FN and BMD-TF, whereas vBMAD-FN showed only positive significant correlation with densitometric parameters (p < 001). In Rett subjects BMD-FN was predicted primarily by weight and movement capacity, whereas vBMAD-FN was predicted by weight, height, and calcium intake. Moreover, AD-SoS was predicted by weight, height, and age, while BTT was predicted only by height. In conclusion, in our study the performance of QUS at phalanges was similar to those of BMD at femur, therefore, both areal BMD at femur and QUS at phalanges (AD-SoS and BTT) may be equally useful in the evaluation of skeletal status in Rett patients.

Osteoporosis in Rett syndrome: a case study presenting a novel management intervention for severe osteoporosis

The present article describes a successful novel therapeutic intervention with Aredia with one child with Rett syndrome, after suffering from six pathological fractures within less than 3 years due to severe osteoporosis. Since the initiation of the treatment (3 years ago), the child has not suffered any fractures. Patients with chronic diseases and those with disabilities or on anticonvulsant medications are at risk for low bone density and possibly for the resultant pathologic fractures that define osteoporosis in children. Individuals with Rett syndrome (RS) have been shown to have low bone mineral density (or osteopenia) at a young age. If osteoporosis occurs in a girl with RS, it can inflict pain and seriously impair the child's mobility and quality of life. The present article describes a case study of a child with RS (showing an average of 1.75 fractures annually for the 4 years preceding the treatment) before and after a treatment with Aredia. Patient received 30 mg/day for 3 days on a once every 3-month cycle. There was a 45 % improvement in bone mass density (BMD) values from pre-post-intervention. The child had no fractures in the 3 years posttreatment. This finding is significant (p < 0.03). The BMD Z-scores of the child showed severe osteoporosis (Z-score of -3.8) at pre-intervention and are elevated to osteopenia levels (Z-score of -1.3) at post-intervention measurements. All measurements suggest that the treatment successfully reversed the osteoporotic process and prevented further fractures. This change caused great relief to the child and her family and an improvement in their quality of life. The findings support the ability (in one case) to reverse the progression of osteoporosis in individuals with Rett syndrome showing severe osteoporosis with multiple fractures.

Pubertal trajectory in females with Rett syndrome: a population-based study

BACKGROUND

Rett syndrome is a severe genetic neurodevelopmental disorder mainly affecting females. The aim of this study was to describe pubertal development in a population-based cohort of females with Rett syndrome.

METHODS

To assess pubertal trajectory we used six waves of data provided by parents of girls and women, recruited through the Australian population-based Rett Syndrome Database. The age at which adrenarche, thelarche or menarche occurred was used as the parameter for time to event (survival) analysis. The relationships between BMI, mutation type and the trajectories were investigated, using Cox proportional hazards.

RESULTS

One quarter of girls reached adrenarche by 9.6 years, half by 11 years and three quarters by 12.6 years. Half reached menarche by 14 years (range 8-23). Being underweight was associated with later age at adrenarche, thelarche and menarche, while higher BMI (overweight) was associated with earlier onset. In general, girls with C-terminal deletions and early truncating mutations reached pubertal stages earlier and those with the p.R168X mutation reached them later.

CONCLUSION

The pubertal course in Rett syndrome may be abnormal, sometimes with early adrenarche but delayed menarche. These features may be genotype dependent and may have varying relationships with growth and bone acquisition.

The relationship between serum ghrelin and body composition with bone mineral density and QUS parameters in subjects with Rett syndrome

Several studies have reported that females with Rett's syndrome frequently have marked decreases in bone mineral density (BMD). However, the pathogenesis of impaired bone status in RTT girls remains controversial. This study aimed to investigate whether ghrelin, an orexigenic peptide secreted by the stomach, was associated with body composition parameters, bone mineral density and quantitative ultrasound (QUS) in girls with Rett's syndrome. In 123 Rett girls (13.6±8.2 years) and in 55 similar age range controls we evaluated ghrelin serum levels, 25OHD, quantitative ultrasound parameters at phalanxes by Bone Profiler-IGEA (amplitude dependent speed of sound: AD-SoS and bone transmission time: BTT), total body bone mineral density (BMD-WB) by Hologic QDR 4500. Whole body mineral content (BMC-WB), BMC-WB/height, fat mass (FM), fat percentage and lean mass (LM) were determined by using the same DXA device. We found that serum ghrelin levels were significantly higher in the Rett patients with respect to the control group (p<0.05). In Rett girls ghrelin serum levels were inversely correlated with both age (R(2)=0.17, p<0.001) and BMI (R(2)=0.14, p<0.001). Moreover, in Rett subjects the values of BMD-WB, BMC-WB, BMC-WB/height and QUS parameters were significantly lower than in control subjects. Fat mass and lean mass were lower in Rett subjects than in controls, but the difference reached the statistical significance only for lean mass. In Rett girls ghrelin serum levels were not predictors of bone status. Instead, we found that in Rett subjects, lean mass, age and 25OHD were significant independent predictors of BMC-WB/h, whereas both age and height were independent predictors of BMD-WB. Moreover, AD-SoS was predicted by age, fat percentage and height; while BTT was predicted only by height. In conclusion, our findings indicate that ghrelin levels were higher in Rett girls with respect to healthy controls, and negatively associated with both DXA and QUS parameters. However, in our study ghrelin was not found to be an independent predictor of bone mass, so supporting the hypothesis that ghrelin is elevated in Rett subjects in a compensatory manner.

Bone mass in Rett syndrome: association with clinical parameters and MECP2 mutations

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by mutations in the MECP2 gene. In 49 female RTT children, aged 1.9-17 y, bone mass was assessed and correlated with clinical parameters and mutations involving the MECP2 gene. We also studied five adult females, aged 20-33 y, and one male child, aged 6 y. Lumbar spine bone mineral content (BMC) and bone mineral density (BMD) were correlated with weight, height, BMI, clinical severity, degree of scoliosis, use of anticonvulsants, and ambulatory status. L1-L4 BMD and BMC showed that 48.9% of them had BMD values >2 SD below age-related norms. BMD values were in the osteoporotic range in the five adult females with RTT. Eleven percent of the children and adults with RTT experienced fractures. Low bone mass was correlated with marginal significance to clinical severity and ambulation but not to scoliosis or anticonvulsant use. Lowest bone mass occurred in patients with T158M or R270X mutations but without statistical significance. Studies in a murine model of RTT confirmed low bone mass as an inherent component of this syndrome. MECP2 mutations and clinical parameters impact bone mass in RTT, but an association with a specific mutation was not demonstrable.

Genomic and transcriptomic analyses distinguish classic Rett and Rett-like syndrome and reveals shared altered pathways

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder characterized by derangements in nervous system especially in cognition and behavior. The present study aims to understand the molecular underpinnings of two subtypes of RTT, classic RTT and Rett-like, and to elucidate common pathways giving rise to common RTT phenotype using genomic and transcriptomic approaches. Mutation screening on selected nuclear genes revealed only MECP2 mutations in a subset of classic RTT patients. MLPA assays and mtDNA screenings were all negative. Genome-wide copy number analysis indicated a novel duplication on X chromosome. Transcriptional profiling revealed blood gene signatures that clearly distinguish classic RTT and RTT-like patients, as well as shared altered pathways in interleukin-4 and NF-κB signaling pathways in both subtypes of the syndrome. To our knowledge, this is the first report on investigating common regulatory mechanisms/signaling pathways that may be relevant to the pathobiology of the "common RTT" phenotype.

Bone ultrasonography at phalanxes in patients with Rett syndrome: a 3-year longitudinal study

Osteopenia is a frequent and early complication of Rett syndrome. This study aimed to evaluate the usefulness of Quantitative Ultrasonography (QUS) at phalanxes in the assessment and monitoring of bone status in Rett patients. We studied 109 girls (10.1+/-6.1 years; range 3-25 years) and 101 age-matched controls. Serum calcium (Ca), bone alkaline phosphatase (B-ALP), parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD) and QUS parameters at phalanxes by Bone Profiler-IGEA (amplitude dependent speed of sound: AD-SoS and bone transmission time: BTT) were measured. At baseline both QUS parameters and 25OHD levels were significantly lower in Rett patients than in controls. Serum 25OHD was inversely correlated with serum PTH and BTT Z-score and BTT Z-score was significantly lower (p<0.05) in the girls with a 25OHD serum levels<or=9 ng/ml. Moreover, multiple regression analysis showed that BTT was significantly influenced by 25OHD levels. The design of the study was to carry out a twelve monthly evaluation of QUS and biochemical parameters for 3-years. 82 Rett patients completed the 36 month longitudinal study. During the study period in the patients, who at baseline were non ambulatory, BTT and AD-SoS Z-score presented the tendency to markedly decrease; in contrast, mild changes of the QUS parameters were observed in patients with severe or mild-moderate ambulatory impairment. Significant difference of BTT Z-score and AD-SoS Z-score among the 3 groups of patients categorized on the basis of ambulatory performance were observed at years 2 and 3. The AD-SoS Z-score at the end of the study period were significantly influenced by the changes in ambulatory performance and the use of anticonvulsant therapy. In conclusion our results suggest the usefulness of QUS parameters at phalanxes in the monitoring of bone status in Rett patients. Low levels of 25OHD and ambulatory impairment play a key role in the skeletal deterioration in Rett girls.

Nurse recognition of early deviation in development in home videos of infants with Rett disorder

BACKGROUND

In the genetic Rett disorder (RD), infants make some progress then suffer a dramatic developmental regression, usually before 2 years of age. Home videos, taken before the problems are recognized, offer an objective source for detecting early signs.

METHODS

Thirty-six health visitors and midwives were invited to view brief examples from home videos of a cohort of 14 infants with RD and 11 control infants with normal development in the first year of life, and to indicate, by pressing a button, points in the recordings which aroused their suspicion of developmental deviation. They were then invited to comment on their selection. The participants were blind as to whether any individual example showed an infant with normal development or one with some form of developmental disturbance.

RESULTS

From the first month of life and throughout the first year, infants with RD received more button presses than controls (46%, 361 out of 778 viewings) in comparison with the control group (12%, 67 of 558). The consistent nature of the health professionals' comments made possible their categorization under four headings: appearance, posture, movement and contact. In the first month of life, the hand postures of infants with RD received particular comment from midwives (23 out of 37 comments overall on posture).

CONCLUSIONS

The present study strongly suggests the presence of early signs of developmental deviation in infants with RD, although, in most cases, formal developmental screening procedures have failed to detect these before the ages of 12 or 18 months.

Describing the phenotype in Rett syndrome using a population database

BACKGROUND

Mutations in the MECP2 gene have been recently identified as the cause of Rett syndrome, prompting research into genotype-phenotype relations. However, despite these genetic advances there has been little descriptive epidemiology of the full range of phenotypes.

AIMS

To describe the variation in phenotype in Rett syndrome using four different scales, by means of a population database.

METHODS

Using multiple sources of ascertainment including the Australian Paediatric Surveillance Unit, the development of an Australian cohort of Rett syndrome cases born since 1976 has provided the first genetically characterised population based study of Rett syndrome. Follow up questionnaires were administered in 2000 to families and used to provide responses for items in four different severity scales.

RESULTS

A total of 199 verified cases of Rett syndrome were reported between January 1993 and July 2000; 152 families provided information for the follow up study. The mean score using the Kerr scale was 22.9 (SD 4.8) and ranged from 20.5 in those under 7 years to 24.2 in those over 17 years. The mean Percy score was 24.9 (SD 6.6) and also increased with age group from 23.0 to 26.9. The mean Pineda score was 16.3 (SD 4.5) and did not differ by age group. The mean WeeFIM was 29.0 (SD 11.9), indicating extreme dependence, and ranged from 18 to 75.

CONCLUSION

We have expanded on the descriptive epidemiology of Rett syndrome and shown different patterns according to the severity scale selected. Although all affected children are severely functionally dependent, it is still possible to identify some variation in ability, even in children with identified MECP2 mutations.

Annotation: Rett syndrome: recent progress and implications for research and clinical practice

BACKGROUND

Rett syndrome was first described 40 years ago as a profoundly disabling condition in girls.

METHOD

Over the last 20 years' national surveys, neuropathological and neurophysiological research have steadily improved understanding of its character and natural history.

RESULTS

In the last two years identification of the causative mutations in the gene methyl CpG binding protein 2 (Xq28) has led to a sudden expansion in knowledge about the underlying developmental disorder, with important implications for clinical practice and new opportunities to develop more effective intervention.

CONCLUSIONS

It is now clear that the disorder occurs in males and females and that there is a wide range in severity.

Rett syndrome: review of biological abnormalities

The Rett syndrome (RS) is a peculiar, sporadic, atrophic disorder, almost entirely confined to females. After the first six months of life there is developmental slowing with reduced communication and head growth for about one year. This is followed by a rapid destructive stage with severe dementia and loss of hand skills (with frequent hand wringing), apraxia and ataxia, autistic features and irregular breathing with hyperventilation. Seizures often supervene. Subsequently there is some stabilization in a pseudo-stationary stage during the preschool to school years, associated with more emotional contact but also abnormalities of the autonomic and skeletal systems. After the age of 15-20 years, a late motor deterioration occurs with dystonia and frequent spasticity but seizures become milder. RS has generally been considered an X-linked disorder in which affected females represent a new mutation, with male lethality. Linkage studies suggested a critical region at Xq28. In 1999, mutations in the gene MECP2 encoding X-linked methyl cytosine-binding protein 2 (MeCP2) were found in a proportion of Rett girls. This protein can bind methylated DNA. Analyses are leading to much further investigation of mutants and their effects on genes. Neuropathological and electrophysiological studies of RS are described. Description of neurometabolic factors includes reduced levels of dopamine, serotonin, noradrenaline and choline acetyltransferase (ChAT) in brain, also estimation of nerve growth factors, endorphin, substance P, glutamate and other amino acids and their receptor levels. The results of neuroimaging are surveyed, including volumetric magnetic resonance imaging (MRI) and positron emission tomography (PET).