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We report on molecular classes in PWS using advanced genomic technology in the largest cohort to date. LOH patterns in UPD15 may impact the risk of having a second genetic condition if the mother carries a recessive mutant allele in the isodisomic region on chromosome 15. The risk of UPD15 may also increase with maternal age.

Background Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1 , the dosage-sensitive gene responsible for Smith–Magenis syndrome (deletion/haploinsufficiency) and Potocki–Lupski syndrome (duplication/triplosensitivity). Methods Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20 . We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes. Results We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20 . The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances. Conclusions TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith–Magenis syndrome. Together with previously described cases, the clinical entity of TCF20 -associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective. Electronic supplementary material The online version of this article (10.1186/s13073-019-0623-0) contains supplementary material, which is available to authorized users.

WHAT'S KNOWN ON THIS SUBJECT:Standardized growth curves do not exist for infants with Prader-Willi syndrome. Syndromespecific growth charts are required for monitoring growth and nutritional status, particularly during growth hormone treatment and follow-up for this disorder during infancy. WHAT THIS STUDY ADDS:Standardized growth curves are reported to be used in monitoring growth and development of infants with Prader-Willi syndrome of both genders from 0 to 36 months of age. abstract OBJECTIVE: To generate and report standardized growth curves for weight, length, head circumference, weight/length, and BMI for nongrowth hormone-treated white infants (boys and girls) with PraderWilli syndrome (PWS) between 0 and 36 months of age. The goal was to monitor growth and compare data with other infants with PWS. METHODS:Anthropometric measures (N ϭ 758) were obtained according to standard methods and analyzed from 186 non-growth hormone-treated white infants (108 boys and 78 girls) with PWS between 0 and 36 months of age. Standardized growth curves were developed and the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles were calculated by using the LMS (refers to , , and ) smoothing procedure method for weight, length, head circumference, weight/ length, and BMI along with the normative 50th percentile using Centers for Disease Control and Prevention national growth data from 2003. The data were plotted for comparison purposes. RESULTS:Five separate standardized growth curves (weight, length, head circumference, weight/length, and BMI) representing 7 percentile ranges were developed from 186 non-growth hormone-treated white male and female infants with PWS aged 0 to 36 months, and the normative 50th percentile was plotted on each standardized infant growth curve. CONCLUSIONS:We encourage the use of these growth standards when examining infants with PWS and evaluating growth for comparison purposes, monitoring for growth patterns, nutritional assessment, and recording responses to growth hormone therapy, commonly used in infants and children with PWS.

OBJECTIVE: The goal of this study was to generate and report standardized growth curves for weight, height, head circumference, and BMI for non-growth hormone-treated white male and female US subjects with Prader-Willi syndrome (PWS) between 3 and 18 years of age and develop standardized growth charts.METHODS: Anthropometric measures (N = 133) were obtained according to standard methods from 120 non-growth hormone-treated white subjects (63 males and 57 females) with PWS between 3 and 18 years of age. Standardized growth curves were developed for the third, 10th, 25th, 50th, 75th, 90th, and 97th percentiles by using the LMS method for weight, height, head circumference, and BMI for PWS subjects along with the normative third, 50th, and 97th percentiles from national and international growth data. The LMS smoothing procedure summarized the distribution of the anthropometric variables at each age using three parameters: power of the Box-Cox transformation l (L), median m (M) and coefficient of variation d (S).RESULTS: Weight, height, head circumference, and BMI standardized growth charts representing 7 percentile ranges were developed from 120 non-growth hormone-treated white male and female US subjects with PWS (age range: 3-18 years) and normative third, 50th, and 97th percentiles from national and international data. CONCLUSIONS:We encourage the use of syndrome-specific growth standards to examine and evaluate subjects with PWS when monitoring growth patterns and determining nutritional and obesity status. These variables can be influenced by culture, individual medical care, diet intervention, and physical activity plans.WHAT'S KNOWN ON THIS SUBJECT: Syndromespecific standardized growth curves are not currently available for non-growth hormonetreated subjects with Prader-Willi syndrome and are required for monitoring growth and development in this rare obesity-related disorder.WHAT THIS STUDY ADDS: Standardized growth curves were useful in monitoring growth and development in these subjects with Prader-Willi syndrome and for the management of growth hormone treatment of both genders, particularly those aged 3 to 18 years. Dr Butler recruited subjects and collected growth data, conceptualized and designed the study, and drafted the initial manuscript; Dr Lee analyzed research data, generated figures, and reviewed the manuscript; Dr Manzardo performed the initial analysis of growth data and revised and reviewed the manuscript; and Drs Gold, Miller, Kimonis, and Driscoll recruited subjects, collected growth data, and reviewed the manuscript. All authors approved the final manuscript as submitted.The content is solely the responsibility of the authors and does not necessarily represent the office views of the National Institutes of Health.This trial has been registered at www.clinicaltrials.gov (identifier NCT00375089). PWS occurs in ∼1 in 15 000 live births and is estimated to affect ∼400 000 people worldwide. It is considered the most common syndromic cause of life-threatening obesity 1 and arises spora...

The A1 kit identified the typical deletions and smaller atypical deletions, whereas the B1 kit was more informative for identifying microdeletions including the IC and SNORD116 regions. Both kits should be made available for accurate characterization of PWS/AS deletion subtypes as well as evaluating for IC and SNORD116 microdeletions.

We describe the National Institutes of Health rare disease consortium for Prader-Willi syndrome (PWS) developed to address concerns regarding medical care, diagnosis, growth and development, awareness, and natural history. PWS results from errors in genomic imprinting leading to loss of paternally expressed genes due to 15q11-q13 deletion, maternal disomy 15 or imprinting defects. The 8 year study was conducted at four national sites on individuals with genetically confirmed PWS and early-onset morbid obesity (EMO) with data accumulated to gain a better understanding of the natural history, cause and treatment of PWS. Enrollment of 355 subjects with PWS and 36 subjects with EMO began in September 2006 with study completion in July 2014. Clinical, genetic, cognitive, behavior, and natural history data were systematically collected along with PWS genetic subtypes, pregnancy and birth history, mortality, obesity, and cognitive status with study details as important endpoints in both subject groups. Of the 355 individuals with PWS, 217 (61%) had the 15q11-q13 deletion, 127 (36%) had maternal disomy 15, and 11 (3%) had imprinting defects. Six deaths were reported in our PWS cohort with 598 cumulative years of study exposure and one death in the EMO group with 42 years of exposure. To our knowledge, this description of a longitudinal study in PWS represents the largest and most comprehensive cohort useful for investigators in planning comparable studies in other rare disorders. Ongoing studies utilizing this database should have a direct impact on care and services, diagnosis, treatment, genotype-phenotype correlations, and clinical outcomes in PWS.

PurposePrader-Willi syndrome (PWS) is an imprinting disorder characterized by typical facial, physical and cognitive/behavioral features, resulting from lack of paternally-expressed genes on chromosome 15q11.2-q13. Studies have suggested an increased risk of other imprinting disorders in children conceived by assisted reproductive techniques (ART). This study was designed to determine the association between ART and PWS.MethodsData on individuals with PWS were collected from three distinct sources and the proportion of ART-births analyzed.ResultsThe proportion of ART-births in the Prader-Willi Syndrome Association [PWSA (USA)], Rare Diseases Clinical Research Network (RDCRN), and University of California, Irvine Medical Center (UCIMC) populations was 1.0% (18/1,736), 1.0% (1/98), and 2.0% (1/50), respectively (overall 1.1%; population frequency for the U.S was 1.0%). Interestingly, 2.4% (45/1,898) of participants were co-twins (eleven born after ART procedures); U.S. twin frequency is 1.6% (p=0.007). The proportion of individuals with maternal disomy 15/imprinting defects born after ART was higher than in the total sample, 55.6% (10/18) and 34.5% (431/1,250), respectively.ConclusionThis study found no association between ART and PWS. There was an increased frequency of twinning. The number of individuals with maternal disomy 15/imprinting defect was nearly double in the ART group compared to the total PWS participants.