Expanding the phenotype of neurofibromatosis type 1 microdeletion syndrome.

Neurofibromatosis type 1 (NF-1) microdeletion syndrome accounts for 5 to 11% of individuals with NF-1. The aim of our study was to characterize a large cohort of individuals with NF-1 microdeletion syndrome and expand its natural history. We conducted a retrospective chart review from 1994 to 2024 of individuals with NF-1 microdeletion syndrome followed at two large Neurofibromatosis Clinics. This cohort consists of 57 individuals with NF-1 microdeletion syndrome (28 type-1, 4 type-2, 2 type-3, 9 atypical deletions, and 14 indeterminate). We note 38/56 (67.9%) with describable facial features, 25/57 (43.8%) with plexiform neurofibromas, and 3/57 (5.2%) with malignant peripheral nerve sheath tumors within the observed period. The most reported neurodevelopmental manifestations from school-age or older individuals included 39/49 (79.6%) with developmental delays, 35/49 (71.4%) with expressive and/or receptive speech delays, 33/41 (80.5%) with learning difficulties, and 23/42 (54.8%) with attention-deficit/hyperactivity disorder. Full-scale IQ testing data was available for 22 individuals (range: 50-96). Of the 21 adults in this cohort, 14/21 (66.7%) graduated from high school, and 4/21 (19.0%) had some college experience. Many individuals received academic support (i.e., special education, individual education plan). In this cohort, neurocognitive outcomes in adults varied more than typically reported in the literature.

Vosoritide therapy in children with achondroplasia aged 3-59 months: a multinational, randomised, double-blind, placebo-controlled, phase 2 trial.

BACKGROUND: Vosoritide is a recombinant C-type natriuretic peptide analogue that increases annualised growth velocity in children with achondroplasia aged 5-18 years. We aimed to assess the safety and efficacy of vosoritide in infants and children younger than 5 years. METHODS: This double-blind, randomised, placebo-controlled, phase 2 trial was done in 16 hospitals across Australia, Japan, the UK, and the USA. Children younger than 60 months with a clinical diagnosis of achondroplasia confirmed by genetic testing and who had completed a baseline growth study or observation period were enrolled into one of three sequential cohorts based on age at screening: 24-59 months (cohort 1); 6-23 months (cohort 2); and 0-5 months (cohort 3). Each cohort included sentinels who received vosoritide to determine appropriate daily drug dose, with the remainder randomly assigned (1:1) within each age stratum (except in Japan, where participants were randomly assigned within each cohort) to receive daily subcutaneous injections of vosoritide (30·0 µg/kg for infants aged 0-23 months; 15·0 µg/kg for children aged 24-59 months) or placebo for 52 weeks. Participants, caregivers, investigators, and the sponsor were masked to treatment assignment. The first primary outcome was safety and tolerability, assessed in all participants who received at least one study dose. The second primary outcome was change in height Z score at 52 weeks from baseline, analysed in all randomly assigned participants. This trial is registered with EudraCT, 2016-003826-18, and ClinicalTrials.gov, NCT03583697. FINDINGS: Between May 13, 2018, and March 1, 2021, 75 participants were recruited (37 [49%] females). 11 were assigned as sentinels, whereas 32 were randomly assigned to receive vosoritide and 32 placebo. Two participants discontinued treatment and the study: one in the vosoritide group (death) and one in the placebo group (withdrawal). Adverse events occurred in all 75 (100%) participants (annual rate 204·5 adverse events per patient in the vosoritide group and 73·6 per patient in the placebo group), most of which were transient injection-site reactions and injection-site erythema. Serious adverse events occurred in three (7%) participants in the vosoritide group (decreased oxygen saturation, respiratory syncytial virus bronchiolitis and sudden infant death syndrome, and pneumonia) and six (19%) participants in the placebo group (petit mal epilepsy, autism, gastroenteritis, vomiting and parainfluenza virus infection, respiratory distress, and skull fracture and otitis media). The least-squares mean difference for change from baseline in height Z score between the vosoritide and placebo groups was 0·25 (95% CI -0·02 to 0·53). INTERPRETATION: Children with achondroplasia aged 3-59 months receiving vosoritide for 52 weeks had a mild adverse event profile and gain in the change in height Z score from baseline. FUNDING: BioMarin Pharmaceutical.

Growth parameters in children with achondroplasia: A 7-year, prospective, multinational, observational study.

PURPOSE: This study was undertaken to collect baseline growth parameters in children with achondroplasia who might enroll in interventional trials of vosoritide, and to establish a historical control. METHODS: In this prospective, observational study, participants (≤17 years) underwent a detailed medical history and physical examination and were followed every 3 months until they finished participating in the study by enrolling in an interventional trial or withdrawing. RESULTS: A total of 363 children were enrolled (28 centers, 8 countries). Mean (SD) follow up was 20.4 (15.0) months. In participants <1 year, mean annualized growth velocity (AGV) was 11.6 cm/year for girls and 14.6 cm/year for boys. By age 1 year, mean AGV decreased to 7.4 cm/year in girls and 7.1 cm/year in boys. By age 10 years, mean AGV decreased to 3.6 cm/year for both sexes. Mean height z-score in participants <1 year was -2.5 for girls and -3.2 for boys and decreased up to the age 5 years (-5.3 for girls; -4.6 for boys). Girls and boys had a disproportionate upper-to-lower body segment ratio. Mean ratio was highest in participants aged <1 year (2.9 for girls; 2.8 for boys) and decreased gradually to approximately 2 in both sexes from 4 years of age onward. CONCLUSION: This study represents one of the largest datasets of prospectively collected medical and longitudinal growth data in children with achondroplasia. It serves as a robust historical control to measure therapeutic interventions against and to further delineate the natural history of this condition.

Infigratinib in children with achondroplasia: the PROPEL and PROPEL 2 studies.

Background: Achondroplasia is the most common short-limbed skeletal dysplasia resulting from gain-of-function pathogenic variants in fibroblast growth factor receptor 3 (FGFR3) gene, a negative regulator of endochondral bone formation. Most treatment options are symptomatic, targeting medical complications. Infigratinib is an orally bioavailable, FGFR1-3 selective tyrosine kinase inhibitor being investigated as a direct therapeutic strategy to counteract FGFR3 overactivity in achondroplasia. Objectives: The main objective of PROPEL is to collect baseline data of children with achondroplasia being considered for future enrollment in interventional studies sponsored by QED Therapeutics. The objectives of PROPEL 2 are to obtain preliminary evidence of safety and efficacy of oral infigratinib in children with achondroplasia, to identify the infigratinib dose to be explored in future studies, and to characterize the pharmacokinetic (PK) profile of infigratinib and major metabolites. Design: PROPEL (NCT04035811) is a prospective, noninterventional clinical study designed to characterize the natural history and collect baseline data of children with achondroplasia over 6-24 months. PROPEL 2 (NCT04265651), a prospective, phase II, open-label study of infigratinib in children with achondroplasia, consists of a dose-escalation, dose-finding, and dose-expansion phase to confirm the selected dose, and a PK substudy. Methods and analysis: Children aged 3-11 years with achondroplasia who completed ⩾6 months in PROPEL are eligible for PROPEL 2. Primary endpoints include treatment-emergent adverse events and change from baseline in annualized height velocity. Four cohorts at ascending dose levels are planned for dose escalation. The selected dose will be confirmed in the dose-expansion phase. Ethics: PROPEL and PROPEL 2 are being conducted in accordance with the International Conference on Harmonization Good Clinical Practice guidelines, principles of the Declaration of Helsinki, and relevant human clinical research and data privacy regulations. Protocols have been approved by local health authorities, ethics committees, and institutions as applicable. Parents/legally authorized representatives are required to provide signed informed consent; signed informed assent by the child is also required, where applicable. Discussion: PROPEL and PROPEL 2 will provide preliminary evidence of the safety and efficacy of infigratinib as precision treatment of children with achondroplasia and will inform the design of future studies of FGFR-targeted agents in achondroplasia. Registration: ClinicalTrials.gov: NCT04035811; NCT04265651.

Robin sequence without cleft palate: Genetic diagnoses and management implications.

Robin sequence (RS), the triad of micrognathia, glossoptosis, and airway obstruction, is a major cause of respiratory distress and feeding difficulties in neonates. Robin sequence can be associated with other medical or developmental comorbidities in ~50% of cases ("syndromic" RS). As well, RS is variably associated with cleft palate (CP). Previous studies have not investigated differences in clinical characteristics of children with RS based on presence or absence of CP. We retrospectively reviewed 175 children with RS and compared genetic diagnoses, medical and developmental comorbidities, severity of airway obstruction, and feeding outcomes between those with and without CP. Strikingly, 45 of 45 (100%) children with RS without CP were classified as syndromic due to presence of comorbidities unrelated to RS, while 83 of 130 (64%) children with RS with CP were classified as syndromic. Among 128 children with syndromic RS, there were no differences in severity of airway obstruction, surgical intervention rate or type, or feeding outcome at 12 months based on CP status. Our findings support the conclusion that the pathogenesis of RS without CP is distinct from RS with CP and more likely to cause additional medical or developmental problems. Alternatively, children with RS without CP and without additional anomalies present may be under recognized.

Safe and persistent growth-promoting effects of vosoritide in children with achondroplasia: 2-year results from an open-label, phase 3 extension study.

PURPOSE: Achondroplasia is caused by pathogenic variants in the fibroblast growth factor receptor 3 gene that lead to impaired endochondral ossification. Vosoritide, an analog of C-type natriuretic peptide, stimulates endochondral bone growth and is in development for the treatment of achondroplasia. This phase 3 extension study was conducted to document the efficacy and safety of continuous, daily vosoritide treatment in children with achondroplasia, and the two-year results are reported. METHODS: After completing at least six months of a baseline observational growth study, and 52 weeks in a double-blind, placebo-controlled study, participants were eligible to continue treatment in an open-label extension study, where all participants received vosoritide at a dose of 15.0 µg/kg/day. RESULTS: In children randomized to vosoritide, annualized growth velocity increased from 4.26 cm/year at baseline to 5.39 cm/year at 52 weeks and 5.52 cm/year at week 104. In children who crossed over from placebo to vosoritide in the extension study, annualized growth velocity increased from 3.81 cm/year at week 52 to 5.43 cm/year at week 104. No new adverse effects of vosoritide were detected. CONCLUSION: Vosoritide treatment has safe and persistent growth-promoting effects in children with achondroplasia treated daily for two years.

CHARGE syndrome in the era of molecular diagnosis: Similar outcomes in those without coloboma or choanal atresia.

CHARGE syndrome (OMIM 214800) is a condition characterized by multisystem involvement with CHD7 pathogenic mutations leading to disease in the majority of patients. Discovery of the molecular cause of CHARGE unmasked a larger phenotypic spectrum than was previously appreciated. Within our interdisciplinary CHARGE syndrome program, we sought to characterize our CHD7-positive CHARGE cohort without coloboma or choanal atresia, highlighting complications and outcomes. We describe 18 individuals with CHD7-confirmed diagnosis from 15 families. The most sensitive finding in the cohort was temporal bone malformations, present in 13/15 individuals. Individuals had an average of 1.6 major features and 3.3 minor features defined by the Blake et al. guidelines. Despite lack of major features or major malformations, the majority of individuals continued to have difficulties with pneumonia, aspiration, secretion management and motility issues that greatly impacted their lives. Our findings illustrate the need for molecular testing and timely recognition given that the major co-morbidities are frequently experienced by patients with the mildest clinical spectrum of CHARGE syndrome.

Mandibulofacial dysostosis with microcephaly: An expansion of the phenotype via parental survey.

Mandibulofacial dysostosis with microcephaly (MFDM) is due to haploinsufficiency of spliceosomal GTPase EFTUD2. Features include microcephaly, craniofacial dysmorphology, developmental disability, and other anomalies. We surveyed parents of individuals with MFDM to expand knowledge about health, development, and parental concerns. Participants included attendees of the inaugural MFDM family conference in June 2019 and members of the MFDM online group. To explore MFDM variable expressivity, we offered targeted Sanger sequencing for untested parents. Forty-seven parents participated in the survey. 59% of individuals with MFDM were male, with mean age 6.4 years (range 8 months to 49 years). Similar to the literature (n = 123), common features include microcephaly, cleft palate, choanal stenosis, tracheoesophageal fistula, heart problems, and seizures. New information includes airway intervention details, age-based developmental outcomes, rate of vision refractive errors, and lower incidences of prematurity and IUGR. Family concerns focused on development, communication, and increased support. Targeted Sanger sequencing for families of seven individuals demonstrated de novo variants, for a total of 91.9% de novo EFTUD2 variants (n = 34/37). This study reports the largest single cohort of individuals with MFDM, expands phenotypic spectrum and inheritance patterns, improves understanding of developmental outcomes and care needs, and identifies development as the biggest concern for parents.

Prenatal diagnosis of Proteus syndrome: Diagnosis of an AKT1 mutation from amniocytes.

Proteus syndrome is a mosaic genetic overgrowth disorder caused by a postzygotic, mosaic activating mutation in AKT1. Rare prenatal presentations include segmental tissue overgrowth, and skeletal and CNS anomalies. We present the first report of prenatally diagnosed and molecularly confirmed Proteus syndrome. Prenatal imaging identified megalencephaly, brain and eye malformations, focal soft tissue enlargement, and ambiguous genitalia. Exome sequencing performed on cultured amniocytes demonstrated an AKT1 pathogenic variant consistent with Proteus syndrome, and postnatal examination confirmed the diagnosis. Postnatal Sanger sequencing could not identify the AKT1 pathogenic variant. This case underscores the importance of prenatal exome sequencing on cultured amniocytes for mosaic overgrowth disorders, as well as provides additional information on the prenatal phenotype of Proteus syndrome, and highlights the impact of prenatal diagnosis on postnatal management.

Once-daily, subcutaneous vosoritide therapy in children with achondroplasia: a randomised, double-blind, phase 3, placebo-controlled, multicentre trial.

BACKGROUND: There are no effective therapies for achondroplasia. An open-label study suggested that vosoritide administration might increase growth velocity in children with achondroplasia. This phase 3 trial was designed to further assess these preliminary findings. METHODS: This randomised, double-blind, phase 3, placebo-controlled, multicentre trial compared once-daily subcutaneous administration of vosoritide with placebo in children with achondroplasia. The trial was done in hospitals at 24 sites in seven countries (Australia, Germany, Japan, Spain, Turkey, the USA, and the UK). Eligible patients had a clinical diagnosis of achondroplasia, were ambulatory, had participated for 6 months in a baseline growth study and were aged 5 to less than 18 years at enrolment. Randomisation was done by means of a voice or web-response system, stratified according to sex and Tanner stage. Participants, investigators, and trial sponsor were masked to group assignment. Participants received either vosoritide 15·0 µg/kg or placebo, as allocated, for the duration of the 52-week treatment period administered by daily subcutaneous injections in their homes by trained caregivers. The primary endpoint was change from baseline in mean annualised growth velocity at 52 weeks in treated patients as compared with controls. All randomly assigned patients were included in the efficacy analyses (n=121). All patients who received one dose of vosoritide or placebo (n=121) were included in the safety analyses. The trial is complete and is registered, with EudraCT, number, 2015-003836-11. FINDINGS: All participants were recruited from Dec 12, 2016, to Nov 7, 2018, with 60 assigned to receive vosoritide and 61 to receive placebo. Of 124 patients screened for eligibility, 121 patients were randomly assigned, and 119 patients completed the 52-week trial. The adjusted mean difference in annualised growth velocity between patients in the vosoritide group and placebo group was 1·57 cm/year in favour of vosoritide (95% CI [1·22-1·93]; two-sided p<0·0001). A total of 119 patients had at least one adverse event; vosoritide group, 59 (98%), and placebo group, 60 (98%). None of the serious adverse events were considered to be treatment related and no deaths occurred. INTERPRETATION: Vosoritide is an effective treatment to increase growth in children with achondroplasia. It is not known whether final adult height will be increased, or what the harms of long-term therapy might be. FUNDING: BioMarin Pharmaceutical.

Systemic and ocular manifestations of a patient with mosaic ARID1A-associated Coffin-Siris syndrome and review of select mosaic conditions with ophthalmic manifestations.

Mosaic genetic mutations may be somatic, germline, or "gonosomal" and have the potential to cause genetic syndromes, disorders, or malformations. Mutations can occur at any point in embryonic development and the timing determines the extent of distribution of the mutation throughout the body and different tissue types. The eye and visual pathway offer a unique opportunity to study somatic and gonosomal mosaic mutations as the eye consists of tissues derived from all three germ layers allowing disease pathology to be assessed with noninvasive imaging. In this review, we describe systemic and ocular manifestations in a child with mosaic Coffin-Siris syndrome. The patient presented with a significant medical history of accommodative esotropia and hyperopia, macrocephaly, polydactyly, global developmental delay, hypotonia, ureteropelvic junction (UPJ) obstruction, and brain MRI abnormalities. The ophthalmic findings in this patient were nonspecific, however, they are consistent with ocular manifestations reported in other patients with Coffin-Siris syndrome. We also review ophthalmic findings of select mosaic chromosomal and single-gene disorders. Ophthalmic assessment alongside clinical genetic testing may play an important role in diagnosis of genetic syndromes as well as understanding disease pathology, particularly when mosaicism plays a role.

Characterization of tracheobronchomalacia in infants with hypophosphatasia.

BACKGROUND: Perinatal and infantile hypophosphatasia (HPP) are associated with respiratory failure and respiratory complications. Effective management of such complications is of key clinical importance. In some infants with HPP, severe tracheobronchomalacia (TBM) contributes to respiratory difficulties. The objective of this study is to characterize the clinical features, investigations and management in these patients. METHODS: We report a case series of five infants with perinatal HPP, with confirmed TBM, who were treated with asfotase alfa and observed for 3-7 years. Additionally, we reviewed respiratory function data in a subgroup of patients with perinatal and infantile HPP included in the clinical trials of asfotase alfa, who required high-pressure respiratory support (positive end-expiratory pressure [PEEP] ≥6 cm H2O and/or peak inspiratory pressure ≥18 cm H2O) during the studies. RESULTS: The case series showed that TBM contributed significantly to respiratory morbidity, and prolonged respiratory support with high PEEP was required. However, TBM improved over time, allowing weaning of all patients from ventilator use. The review of clinical trial data included 20 patients and found a high degree of heterogeneity in PEEP requirements across the cohort; median PEEP was 8 cm H2O at any time and some patients presented with high PEEP (≥8 cm H2O) over periods of more than 6 months. CONCLUSION: In infants with HPP presenting with persistent respiratory complications, it is important to screen for TBM and initiate appropriate respiratory support and treatment with asfotase alfa at an early stage. TRIAL REGISTRATION: ClinicalTrials.gov numbers: NCT00744042 , registered 27 August 2008; NCT01205152 , registered 17 September 2010; NCT01176266 , registered 29 July 2010.

Homozygous missense variant in BMPR1A resulting in BMPR signaling disruption and syndromic features.

BACKGROUND: The bone morphogenetic protein (BMP) pathway is known to play an imperative role in bone, cartilage, and cardiac tissue formation. Truncating, heterozygous variants, and deletions of one of the essential receptors in this pathway, Bone Morphogenetic Protein Receptor Type1A (BMPR1A), have been associated with autosomal dominant juvenile polyposis. Heterozygous deletions have also been associated with cardiac and minor skeletal anomalies. Populations with atrioventricular septal defects are enriched for rare missense BMPR1A variants. METHODS: We report on a patient with a homozygous missense variant in BMPR1A causing skeletal abnormalities, growth failure a large atrial septal defect, severe subglottic stenosis, laryngomalacia, facial dysmorphisms, and developmental delays. RESULTS: Functional analysis of this variant shows increased chondrocyte death for cells with the mutated receptor, increased phosphorylated R-Smads1/5/8, and loss of Sox9 expression mediated by decreased phosphorylation of p38. CONCLUSION: This homozygous missense variant in BMPR1A appears to cause a distinct clinical phenotype.

Using human sequencing to guide craniofacial research.

A recent convergence of technological innovations has re-energized the ability to apply genetics to research in human craniofacial development. Next-generation exome and whole genome sequencing have significantly dropped in price, making it relatively trivial to sequence and analyze patients and families with congenital craniofacial anomalies. A concurrent revolution in genome editing with the use of the CRISPR-Cas9 system enables the rapid generation of animal models, including mouse, which can precisely recapitulate human variants. Here, we summarize the choices currently available to the research community. We illustrate this approach with the study of a family with a novel craniofacial syndrome with dominant inheritance pattern. The genomic analysis suggested a causal variant in AMOTL1 which we modeled in mice. We also made a novel deletion allele of Amotl1. Our results indicate that Amotl1 is not required in the mouse for survival to weaning. Mice carrying the variant identified in the human sequencing studies, however, do not survive to weaning in normal ratios. The cause of death is not understood for these mice complicating our conclusions about the pathogenicity in the index patient. Thus, we highlight some of the powerful opportunities and confounding factors confronting current craniofacial genetic research.

Fowler syndrome and fetal MRI findings: a genetic disorder mimicking hydranencephaly/hydrocephalus.

Fetal ventriculomegaly is a common referral for prenatal MRI, with possible etiologies being hydrocephalus and hydranencephaly. The underlying cause of hydranencephaly is unknown, but many have suggested that the characteristic supratentorial injury is related to idiopathic bilateral occlusions of the internal carotid arteries from an acquired or destructive event. Fowler syndrome is a rare genetic disorder that causes fetal akinesia and a proliferative vasculopathy that can result in an apparent hydranencephaly-hydrocephaly complex. On prenatal imaging, the presence of significant parenchymal loss in the supratentorial and infratentorial brain is a clue to the diagnosis, which should prompt early genetic testing.

Family History Collection Practices: National Survey of Pediatric Primary Care Providers.

While family history (FH) collection is a core responsibility of pediatric primary care providers (PCPs), few details about this practice are known. We surveyed a random national sample of 1200 pediatricians and family medicine physicians about FH collection practices. A total of 86% of respondents (n = 289 pediatricians; n = 152 family medicine physicians) indicated that they collect a FH "always" or "most of the time" with 77% reporting collection at the first visit, regardless of whether it is a health maintenance or problem-focused visit. Less than half ask about relatives other than parents, siblings, or grandparents (36.3%). Among respondents, 42% routinely update the FH at every health maintenance visit while 6% updated FH at every visit. Pediatric PCPs use a variety of methods to collect a FH that is limited in scope and variably updated. Our results suggest that interventions are needed to help pediatric PCPs collect a systematic, efficient, and updated FH.

Monitoring guidance for patients with hypophosphatasia treated with asfotase alfa.

Hypophosphatasia (HPP) is a rare, inherited, systemic, metabolic disorder caused by autosomal recessive mutations or a single dominant-negative mutation in the gene encoding tissue-nonspecific alkaline phosphatase (TNSALP). The disease is associated with a broad range of signs, symptoms, and complications, including impaired skeletal mineralization, altered calcium and phosphate metabolism, recurrent fractures, pain, respiratory problems, impaired growth and mobility, premature tooth loss, developmental delay, and seizures. Asfotase alfa is a human, recombinant enzyme replacement therapy that is approved in many countries for the treatment of patients with HPP. To address the unmet need for guidance in the monitoring of patients receiving asfotase alfa, an international panel of physicians with experience in diagnosing and managing HPP convened in May 2016 to discuss treatment monitoring parameters. The panel discussions focused on recommendations for assessing and monitoring patients after the decision to treat with asfotase alfa had been made and did not include recommendations for whom to treat. Based on the consensus of panel members, this review provides guidance on the monitoring of patients with HPP during treatment with asfotase alfa, including recommendations for laboratory, efficacy, and safety assessments and the frequency with which these should be performed during the course of treatment. Recommended assessments are based on patient age and include regular monitoring of biochemistry, skeletal radiographs, respiratory function, growth, pain, mobility and motor function, and quality of life. Because of the systemic presentation of HPP, a coordinated, multidisciplinary, team-based, patient-focused approach is recommended in the management of patients receiving asfotase alfa. Monitoring of efficacy and safety outcomes must be tailored to the individual patient, depending on medical history, clinical manifestations, availability of resources in the clinical setting, and the clinician's professional judgment.