Systematic cascade screening in the Danish Fabry Disease Centre: 20 years of a national single-centre experience.

The lysosomal storage disorder Fabry disease is caused by deficient or absent activity of the GLA gene enzyme α-galactosidase A. In the present study we present the molecular and biochemical data of the Danish Fabry cohort and report 20 years' (2001-2020) experience in cascade genetic screening at the Danish National Fabry Disease Center. The Danish Fabry cohort consisted of 26 families, 18 index patients (9 males and 9 females, no available data for 8 index-patients) and 97 family members with a pathogenic GLA variant identified by cascade genetic testing (30 males and 67 females). Fourteen patients (5 males and 9 females; mean age of death 47.0 and 64.8 years respectively) died during follow-up. The completeness of the Fabry patient identification in the country has resulted in a cohort of balanced genotypes according to gender (twice number of females compared to males), indicating that the cohort was not biased by referral, and further resulted in earlier diagnosis of the disease by a lower age at diagnosis in family members compared to index-patients (mean age at diagnosis: index-patients 42.2 vs. family members 26.0 years). Six previously unreported disease-causing variants in the GLA gene were discovered. The nationwide screening and registration of Fabry disease families provide a unique possibility to establish a complete cohort of Fabry patients and to advance current knowledge of this inherited rare lysosomal storage disorder.

Long-term safety and outcomes in hereditary tyrosinaemia type 1 with nitisinone treatment: a 15-year non-interventional, multicentre study.

BACKGROUND: Since the EU approval of nitisinone in 2005, prognosis for patients with hereditary tyrosinaemia type 1 has changed dramatically, with patients living with the disease now reaching adulthood for the first time in history. This study aimed to assess the long-term safety and outcomes of nitisinone treatment in patients with hereditary tyrosinaemia type 1. METHODS: We did a non-interventional, non-comparative, multicentre study in 77 sites across 17 countries in Europe and collected retrospective and prospective longitudinal data in patients with hereditary tyrosinaemia type 1 who were treated with oral nitisinone during the study period (Feb 21, 2005, to Sept 30, 2019). There were no specific exclusion criteria. Patients were followed-up with an investigator at least annually for as long as they were treated, or until the end of the study. The primary endpoints, occurrence of adverse events related to hepatic, renal, ophthalmic, haematological, or cognitive or developmental function, were assessed in the complete set (all patients already receiving treatment at the index date [Feb 21, 2005] or starting treatment thereafter) and the index set (the subset of patients who had their first dose on the index date or later only). FINDINGS: 315 patients were enrolled during the study period (complete set). Additionally, data from 24 patients who had liver transplantation or died during the post-marketing surveillance programme were retrieved (extended analysis set; 339 patients). Median treatment duration was 11·2 years (range 0·7-28·4); cumulative nitisinone exposure was 3172·7 patient-years. Patients who were diagnosed by neonatal screening started nitisinone treatment at median age 0·8 months versus 8·5 months in those who presented clinically. Incidences of hepatic, renal, ophthalmic, haematological, or cognitive or developmental adverse events were low. Occurrence of liver transplantation or death was more frequent the later that treatment was initiated (none of 70 patients who started treatment at age <28 days vs 35 [13%] of 268 patients who started treatment at age ≥28 days). 279 (89%) of 315 patients were assessed as having either very good or good nitisinone treatment compliance. Treatment and diet compliance declined as patients aged. Suboptimal plasma phenylalanine and tyrosine levels were observed. The majority of patients were reported to have good overall clinical condition throughout treatment; 176 (87%) of 203 during the entire study, 98% following 1 year of treatment. INTERPRETATION: Long-term nitisinone treatment was well tolerated and no new safety signals were revealed. Life-limiting hepatic disease appears to have been prevented by early treatment start. Neonatal screening was the most effective way of ensuring early treatment. Standardised monitoring of blood tyrosine, phenylalanine, and nitisinone levels has potential to guide individualised therapy. FUNDING: Swedish Orphan Biovitrum (Sobi).

Cystic fibrosis newborn screening in Denmark: Experience from the first 2 years.

BACKGROUND: In Denmark, newborn screening (NBS) for cystic fibrosis (CF) was introduced on 1 May 2016. The implementation and results from the first 2 years of the national newborn CF screening program are presented. METHODS: The screening included immunoreactive trypsinogen (IRT), followed by evaluation for the F508del mutation when a value at or above the 50 ng/mL cutoff was present. In cases with a single F508del mutation or a very high IRT value above 145 ng/mL, next-generation sequencing of the CF transmembrane conductance regulator gene (CFTR) was performed. RESULTS: Of 126 522 newborn infants 126 338 were tested (99.85%), and 4730 samples (3.7%) were assessed for CFTR mutations. Twenty-six infants were screen-positive and referred for diagnostic follow-up of whom 22 were confirmed to have a CF diagnosis, four had one known and one CFTR allele with unknown pathogenicity, classified as cystic fibrosis screening positive inconclusive diagnosis (CFSPID), PPV 84.6%. One of the four children classified as CFSPID was later found to carry the two identified CFTR variants in cis and was reclassified as a carrier of CF. We found two false negatives; one exhibited an IRT level above the 50 ng/mL cutoff but was below the 145 ng/mL very high cutoff and with no F508del mutation present. The second false-negative fell below the 50 ng/mL IRT cutoff but was diagnosed shortly after birth on the basis of meconium ileus. Screening sensitivity, 91.7%. Two hundred thirty-two children were identified as carriers of CF, which is twofold above the estimated annual number of carriers. All but one carrier were heterozygous for the F508del CFTR mutation. Sixteen percent of the sequenced samples revealed rare CFTR variants, which were classified as nonpathogenic in relation to CF. CONCLUSIONS: During the first 2 years of NBS CF screening in Denmark, we identified close to the expected number of infants with CF using an algorithm based on IRT, presence of F508del mutation and comprehensive genetic analysis. CFSPID accounted for only a small minority, despite comprehensive CFTR sequencing, whereas more carriers than initially expected were identified.

Real-World Outcomes with Lomitapide Use in Paediatric Patients with Homozygous Familial Hypercholesterolaemia.

INTRODUCTION: Homozygous familial hypercholesterolaemia (HoFH) is a rare, autosomal disease affecting the clearance of low-density lipoprotein cholesterol (LDL-C) from circulation, and leading to early-onset atherosclerotic cardiovascular disease (ASCVD). Treatment consists mainly of statins, lipoprotein apheresis (LA) and, more recently, the microsomal triglyceride transfer protein inhibitor lomitapide. Lomitapide is not licensed for use in children, but has been made available through an expanded access programme or on a named patient basis. METHODS: This case series includes 11 HoFH patients in 10 different centres in eight countries, less than 18 years of age (mean 11.6 ± 1.1 years, 64% male), with signs of ASCVD, and who have received treatment with lomitapide (mean dose 24.5 ± 4.3 mg/day; mean exposure 20.0 ± 2.9 months). Background lipid-lowering therapy was given according to local protocols. Lomitapide was commenced with a stepwise dose escalation from 2.5 mg or 5 mg/day; dietary advice and vitamin supplements were provided as per the product label for adults. Laboratory analysis was conducted as part of regular clinical care. RESULTS: In the 11 cases, mean baseline LDL-C was 419 ± 74.6 mg/dL and was markedly reduced by lomitapide to a nadir of 176.7 ± 46.3 mg/dL (58.4 ± 6.8% decrease). Six patients achieved recommended target levels for children below 135 mg/dL, five of whom had LA frequency reduced. In one case, LDL-C levels were close to target when lomitapide was started but remained stable despite 75% reduction in LA frequency (from twice weekly to biweekly). Adverse events were mainly gastrointestinal in nature, occurred early in the treatment course and were well managed. Three patients with excursions in liver function tests were managed chiefly without intervention; two patients had decreases in lomitapide dose. CONCLUSIONS: Lomitapide demonstrated promising effectiveness in paediatric HoFH patients. Adverse events were manageable, and the clinical profile of the drug is apparently similar to that in adult patients. FUNDING: Amryt Pharma.

Phenotype, treatment practice and outcome in the cobalamin-dependent remethylation disorders and MTHFR deficiency: Data from the E-HOD registry.

AIM: To explore the clinical presentation, course, treatment and impact of early treatment in patients with remethylation disorders from the European Network and Registry for Homocystinurias and Methylation Defects (E-HOD) international web-based registry. RESULTS: This review comprises 238 patients (cobalamin C defect n = 161; methylenetetrahydrofolate reductase deficiency n = 50; cobalamin G defect n = 11; cobalamin E defect n = 10; cobalamin D defect n = 5; and cobalamin J defect n = 1) from 47 centres for whom the E-HOD registry includes, as a minimum, data on medical history and enrolment visit. The duration of observation was 127 patient years. In 181 clinically diagnosed patients, the median age at presentation was 30 days (range 1 day to 42 years) and the median age at diagnosis was 3.7 months (range 3 days to 56 years). Seventy-five percent of pre-clinically diagnosed patients with cobalamin C disease became symptomatic within the first 15 days of life. Total homocysteine (tHcy), amino acids and urinary methylmalonic acid (MMA) were the most frequently assessed disease markers; confirmatory diagnostics were mainly molecular genetic studies. Remethylation disorders are multisystem diseases dominated by neurological and eye disease and failure to thrive. In this cohort, mortality, thromboembolic, psychiatric and renal disease were rarer than reported elsewhere. Early treatment correlates with lower overall morbidity but is less effective in preventing eye disease and cognitive impairment. The wide variation in treatment hampers the evaluation of particular therapeutic modalities. CONCLUSION: Treatment improves the clinical course of remethylation disorders and reduces morbidity, especially if started early, but neurocognitive and eye symptoms are less responsive. Current treatment is highly variable. This study has the inevitable limitations of a retrospective, registry-based design.

Newborn screening for homocystinurias: Recent recommendations versus current practice.

PURPOSE: To assess how the current practice of newborn screening (NBS) for homocystinurias compares with published recommendations. METHODS: Twenty-two of 32 NBS programmes from 18 countries screened for at least one form of homocystinuria. Centres provided pseudonymised NBS data from patients with cystathionine beta-synthase deficiency (CBSD, n = 19), methionine adenosyltransferase I/III deficiency (MATI/IIID, n = 28), combined remethylation disorder (cRMD, n = 56) and isolated remethylation disorder (iRMD), including methylenetetrahydrofolate reductase deficiency (MTHFRD) (n = 8). Markers and decision limits were converted to multiples of the median (MoM) to allow comparison between centres. RESULTS: NBS programmes, algorithms and decision limits varied considerably. Only nine centres used the recommended second-tier marker total homocysteine (tHcy). The median decision limits of all centres were ≥ 2.35 for high and ≤ 0.44 MoM for low methionine, ≥ 1.95 for high and ≤ 0.47 MoM for low methionine/phenylalanine, ≥ 2.54 for high propionylcarnitine and ≥ 2.78 MoM for propionylcarnitine/acetylcarnitine. These decision limits alone had a 100%, 100%, 86% and 84% sensitivity for the detection of CBSD, MATI/IIID, iRMD and cRMD, respectively, but failed to detect six individuals with cRMD. To enhance sensitivity and decrease second-tier testing costs, we further adapted these decision limits using the data of 15 000 healthy newborns. CONCLUSIONS: Due to the favorable outcome of early treated patients, NBS for homocystinurias is recommended. To improve NBS, decision limits should be revised considering the population median. Relevant markers should be combined; use of the postanalytical tools offered by the CLIR project (Collaborative Laboratory Integrated Reports, which considers, for example, birth weight and gestational age) is recommended. tHcy and methylmalonic acid should be implemented as second-tier markers.

Age-related renal function decline in Fabry disease patients on enzyme replacement therapy: a longitudinal cohort study.

BACKGROUND: Nephropathy is common in Fabry disease (FD). Prior studies of renal function during enzyme replacement therapy (ERT) have primarily used estimated glomerular filtration rate (eGFR). We studied the attrition of renal function in FD by measured GFR (mGFR) and urine protein excretion, and explored the influence of age. METHODS: This was a long-term observational study of a nationwide, family-screened cohort of FD patients. All Danish genetically verified FD patients on ERT, without end-stage renal disease at baseline and with three or more mGFR values were included. RESULTS: In all, 52 patients with consecutive mGFR values (n = 841) over median 7 years (range 1-13) were evaluated. Blood pressure remained normal and urine protein excretion was unchanged. Plasma globotriaosylceramide (Gb-3) levels normalized while plasma lyso-Gb-3 remained abnormal in 34% of patients. Baseline mGFR was 90 ± 3 mL/min/1.73 m2 and rate of renal function loss 0.9 ± 0.2 mL/min/1.73 m2/year. Baseline eGFR was 97 ± 5 mL/min/1.73 m2 and rate of renal function loss 0.8 ± 0.3 mL/min/1.73 m2/year. mGFR was age- adjusted to renal healthy non-FD subjects, giving a standard deviation score of -0.8 ± 0.2 with an annual slope of -0.03 ± 0.01 (P = 0.099), without differences between genders. Age grouping of age-adjusted data showed exaggerated renal function loss with age. Urine albumin-creatinine ratio (UACR) >300 mg/g was associated with faster renal function loss, independent of baseline mGFR, age and gender. CONCLUSIONS: ERT-treated FD patients did not have a faster attrition of renal function than renal healthy non-FD subjects (background population). The rate of renal function loss with age was independent of gender and predicted by high UACR. We suggest cautious interpretation of non-age-adjusted FD renal data.

Hyperglucagonemia correlates with plasma levels of non-branched-chain amino acids in patients with liver disease independent of type 2 diabetes.

Patients with type 2 diabetes (T2D) and patients with nonalcoholic fatty liver disease (NAFLD) frequently exhibit elevated plasma concentrations of glucagon (hyperglucagonemia). Hyperglucagonemia and α-cell hyperplasia may result from elevated levels of plasma amino acids when glucagon's action on hepatic amino acid metabolism is disrupted. We therefore measured plasma levels of glucagon and individual amino acids in patients with and without biopsy-verified NAFLD and with and without type T2D. Fasting levels of amino acids and glucagon in plasma were measured, using validated ELISAs and high-performance liquid chromatography, in obese, middle-aged individuals with I) normal glucose tolerance (NGT) and NAFLD, II) T2D and NAFLD, III) T2D without liver disease, and IV) NGT and no liver disease. Elevated levels of total amino acids were observed in participants with NAFLD and NGT compared with NGT controls (1,310 ± 235 µM vs. 937 ± 281 µM, P = 0.03) and in T2D and NAFLD compared with T2D without liver disease (1,354 ± 329 µM vs. 511 ± 235 µM, P < 0.0001). Particularly amino acids with known glucagonotropic effects (e.g., glutamine) were increased. Plasma levels of total amino acids correlated to plasma levels of glucagon also when adjusting for body mass index (BMI), glycated hemoglobin (HbA1c), and cholesterol levels (ß = 0.013 ± 0.007, P = 0.024). Elevated plasma levels of total amino acids associate with hyperglucagonemia in NAFLD patients independently of glycemic control, BMI or cholesterol - supporting the potential importance of a "liver-α-cell axis" in which glucagon regulates hepatic amino acid metabolism. Fasting hyperglucagonemia as seen in T2D may therefore represent impaired hepatic glucagon action with increasing amino acids levels. NEW & NOTEWORTHY Hypersecretion of glucagon (hyperglucagonemia) has been suggested to be linked to type 2 diabetes. Here, we show that levels of amino acids correlate with levels of glucagon. Hyperglucagonemia may depend on hepatic steatosis rather than type 2 diabetes.

Health Related Quality of Life, Disability, and Pain in Alpha Mannosidosis: Long-Term Data of Enzyme Replacement Therapy With Velmanase Alfa (Human Recombinant Alpha Mannosidase)

Abstract Alpha-mannosidosis, a rare lysosomal storage disorder caused by deficiency of the lysosomal enzyme alpha-mannosidase, results in accumulation of mannose-rich glycoproteins in the tissues and sequelae leading to intellectual disability, ataxia, impaired hearing and speech, recurrent infections, skeletal abnormalities, muscular pain, and weakness. This study aimed to investigate disability, pain, and overall health using the Childhood Health Assessment Questionnaire (CHAQ) and the EuroQol 5 Dimension-5 Level Questionnaire (EQ-5D-5L) in patients with alpha-mannosidosis participating in rhLAMAN-10, a phase III open-label, clinical trial of velmanase alfa, a recombinanthumanlysosomalalpha-mannosidase. Long-termprognosesformost patients withuntreatedalpha-mannosidosisarepoor due to progressive neuromuscular, skeletal, and intellectual deterioration, leading to increased dependence in mobility and activities of daily living and increased caregiver and health-care burden. Long-term CHAQ and EQ-5D-5L data highlight improvement trends in health-related quality of life and a reduction in disability and pain in patients receiving up to 48 months of velmanase alfa treatment.

The D313Y variant in the GLA gene - no evidence of a pathogenic role in Fabry disease.

Fabry disease is an X- linked inherited lysosomal storage disease caused by mutations in the GLA gene encoding the lysosomal enzyme alpha-galactosidase A (α-Gal A). The possible pathological significance of the D313Y variant in the GLA gene has not been verified and it may be a Fabry variant. Our aim was to elucidate whether the presence of the D313Y variant influenced the α-Gal A activity or resulted in Fabry symptoms or Fabry organ involvement. In two Danish families the presence of the D313Y variant did not result in reduced α-Gal A activity or clinical Fabry manifestations in males, and the presence in Fabry females did not significantly enhance the phenotype of a known causative mutation in the GLA gene (G271S). Our findings indicate that the D313Y variant is not causative to nor enhancing Fabry disease phenotype. The D313Y variant in the GLA gene was not disease causative in 2 Danish families. Investigating male family members were crucial in excluding the Fabry phenotype, and thus very important for proper genetic counceling of all family members, as well as overdiagnosing a devastating genetic disease.

A study of the clinical and radiological features in a cohort of 93 patients with a COL2A1 mutation causing spondyloepiphyseal dysplasia congenita or a related phenotype.

Type 2 collagen disorders encompass a diverse group of skeletal dysplasias that are commonly associated with orthopedic, ocular, and hearing problems. However, the frequency of many clinical features has never been determined. We retrospectively investigated the clinical, radiological, and genotypic data in a group of 93 patients with molecularly confirmed SEDC or a related disorder. The majority of the patients (80/93) had short stature, with radiological features of SEDC (n = 64), others having SEMD (n = 5), Kniest dysplasia (n = 7), spondyloperipheral dysplasia (n = 2), or Torrance-like dysplasia (n = 2). The remaining 13 patients had normal stature with mild SED, Stickler-like syndrome or multiple epiphyseal dysplasia. Over 50% of the patients had undergone orthopedic surgery, usually for scoliosis, femoral osteotomy or hip replacement. Odontoid hypoplasia was present in 56% (95% CI 38-74) and a correlation between odontoid hypoplasia and short stature was observed. Atlanto-axial instability, was observed in 5 of the 18 patients (28%, 95% CI 10-54) in whom flexion-extension films of the cervical spine were available; however, it was rarely accompanied by myelopathy. Myopia was found in 45% (95% CI 35-56), and retinal detachment had occurred in 12% (95% CI 6-21; median age 14 years; youngest age 3.5 years). Thirty-two patients complained of hearing loss (37%, 95% CI 27-48) of whom 17 required hearing aids. The ophthalmological features and possibly also hearing loss are often relatively frequent and severe in patients with splicing mutations. Based on clinical findings, age at onset and genotype-phenotype correlations in this cohort, we propose guidelines for the management and follow-up in this group of disorders.

Carnitine levels in 26,462 individuals from the nationwide screening program for primary carnitine deficiency in the Faroe Islands.

BACKGROUND: Primary carnitine deficiency (PCD) is an autosomal recessive disorder of fatty acid oxidation and has been associated to episodes of sudden death in the Faroe Islands. Data are presented from the nationwide population based Faroese screening program to find people with low carnitine levels indicating PCD. METHODS: Whole blood samples from dried blood spots were analysed by tandem mass spectrometry with and without butylation. Genetic analyses were performed in all people with non-butylated free carnitine (fC0) below 7 µmol/L. RESULTS: 55 % (n = 26,462) of the entire population was screened and 89 PCD patients were identified, yielding an overall prevalence of 1:297 of PCD in the Faroe Islands. Carnitine levels were positively correlated to age in both males and females (p < 0.003) although levels decreased in females when reaching fertile age. The gender difference in mean carnitine levels was significant during female fertile age (4.71 µmol/L fC0 in the age group 25-30 years, p < 0.01). A lower cut-off of 5 µmol/L in fC0 identified all homozygous for the severe genotype c.95A > G (p.N32S) (n = 20). CONCLUSION: Carnitine levels differ by gender and age. A lower cut-off of 5 µmol/L in fC0 was appropriate to identify c.95A > G homozygotes. The prevalence of PCD in the Faroe Islands is the highest reported in the world (1:297).

Primary Carnitine deficiency in the Faroe Islands: health and cardiac status in 76 adult patients diagnosed by screening.

BACKGROUND: Carnitine deficiency can cause cardiomyopathy and cardiac arrhythmia. The prevalence in the Faroe Islands is the highest reported in the world (1:300). A nationwide screening program identified 76 Faroese adult patients (15-80 years) with Primary Carnitine Deficiency (PCD). We describe prior and current health status and symptoms in these patients, especially focusing on cardiac characteristics. METHODS: Upon identification, patients were immediately admitted for physical examination, ECG, blood tests and initiation of L-carnitine supplementation. Medical records were reviewed and patients were interviewed. Echocardiography and blood tests were performed in 35 patients before and after L-carnitine supplementation. RESULTS: All patients were either asymptomatic or had minor symptoms when diagnosed. Echocardiography including LVEF, global longitudinal strain and dimensions were normal apart from left ventricular hypertrophy with normal systolic function in one young male. Symptoms, e.g. fatigue, were reported in 43 % with a reduction to 12 % (p < 0.01) following initiation of L-carnitine supplementation. Eighty two % reported participation in sports of which 52 % were on a competitive level. ECGs showed limited changes and blood tests were normal. Mean plasma free carnitine increased from 6.1 µmol/L to 15.1 µmol/L (p < 0.01) within 50 days of L-carnitine supplementation. CONCLUSION: PCD in adults can cause serious symptoms, but adult Faroese patients identified through a screening program were predominantly asymptomatic with a normal cardiac structure and function.

Four patients with Sillence type I osteogenesis imperfecta and mild bone fragility, complicated by left ventricular cardiac valvular disease and cardiac tissue fragility caused by type I collagen mutations.

Osteogenesis imperfecta (OI) type I is a hereditary disorder of connective tissue (HDCT) characterized by blue or gray sclerae, variable short stature, dentinogenesis imperfecta, hearing loss, and recurrent fractures from infancy. We present four examples of OI type I complicated by valvular heart disease and associated with tissue fragility. The diagnosis of a type I collagen disorder was confirmed by abnormal COL1A1 or COL1A2 gene sequencing. One patient was investigated with electrophoresis of collagens from cultured skin fibroblasts, showing structurally abnormal collagen type I, skin biopsy showed unusual histology and abnormal collagen fibril ultra-structure at electron microscopy. The combined clinical, surgical, histological, ultra-structural, and molecular genetic data suggest the type I collagen defect as contributory to cardiac valvular disease. The degree of tissue fragility experienced at cardiac surgery in these individuals, also reported in a small number of similar case reports, suggests that patients with OI type I need careful pre-operative assessment and consideration of the risks and benefits of cardiac surgery.

Novel cases of D-2-hydroxyglutaric aciduria with IDH1 or IDH2 mosaic mutations identified by amplicon deep sequencing.

BACKGROUND: Mosaic IDH1 mutations are described as the cause of metaphyseal chondromatosis with increased urinary excretion of D-2-hydroxyglutarate (MC-HGA), and mutations in IDH2 as the cause of D-2-hydroxyglutaric aciduria (D-2HGA) type II. Mosaicism for IDH2 mutations has not previously been reported as a cause of D-2HGA. Here we describe three cases: one MC-HGA case with IDH1 mosaic mutations, and two D-2HGA type II cases. In one D-2HGA case we identified mosaicism for an IDH2 mutation as the genetic cause of this disorder; the other D-2HGA case was caused by a heterozygous IDH2 mutation, while the unaffected mother was a mosaic carrier. METHODS: We performed amplicon deep sequencing using the 454 GS Junior platform, next to Sanger sequencing, to identify and confirm mosaicism of IDH1 or IDH2 mutations in MC-HGA or D-2HGA, respectively. RESULTS AND CONCLUSIONS: We identified different mutant allele percentages in DNA samples derived from different tissues (blood vs fibroblasts). Furthermore, we found that mutant allele percentages of IDH1 decreased after more passages had occurred in fibroblast cell cultures. We describe a method for the detection and validation of mosaic mutations in IDH1 and IDH2, making quantification with laborious cloning techniques obsolete.

Mutation-based growth charts for SEDC and other COL2A1 related dysplasias.

From data collected via a large international collaborative study, we have constructed a growth chart for patients with molecularly confirmed congenital spondylo-epiphyseal dysplasia (SEDC) and other COL2A1 related dysplasias. The growth chart is based on longitudinal height measurements of 79 patients with glycine substitutions in the triple-helical domain of COL2A1. In addition, measurements of 27 patients with other molecular defects, such as arginine to cysteine substitutions, splice mutations, and mutations in the C-terminal propeptide have been plotted on the chart. Height of the patients progressively deviate from that of normal children: compared to normal WHO charts, the mean length/height is -2.6 SD at birth, -4.2 SD at 5 years, and -5.8 SD in adulthood. The mean adult height (male and female combined) of patients with glycine substitutions in the triple-helical region is 138.2 cm but there is a large variation. Patients with glycine to cysteine substitutions tend to cluster within the upper part of the chart, while patients with glycine to serine or valine substitutions are situated between +1 SD and -1 SD. Patients with carboxy-terminal glycine substitutions tend to be shorter than patients with amino-terminal substitutions, while patients with splice mutations are relatively tall. However, there are exceptions and specific mutations can have a strong or a relatively mild negative effect on growth. The observation of significant difference in adult height between affected members of the same family indicates that height remains a multifactorial trait even in the presence of a mutation with a strong dominant effect.

Mucopolysaccharidosis type II: European recommendations for the diagnosis and multidisciplinary management of a rare disease.

UNLABELLED: Mucopolysaccharidosis type II (MPS II) is a rare, life-limiting, X-linked recessive disease characterised by deficiency of the lysosomal enzyme iduronate-2-sulfatase. Consequent accumulation of glycosaminoglycans leads to pathological changes in multiple body systems. Age at onset, signs and symptoms, and disease progression are heterogeneous, and patients may present with many different manifestations to a wide range of specialists. Expertise in diagnosing and managing MPS II varies widely between countries, and substantial delays between disease onset and diagnosis can occur. In recent years, disease-specific treatments such as enzyme replacement therapy and stem cell transplantation have helped to address the underlying enzyme deficiency in patients with MPS II. However, the multisystem nature of this disorder and the irreversibility of some manifestations mean that most patients require substantial medical support from many different specialists, even if they are receiving treatment. This article presents an overview of how to recognise, diagnose, and care for patients with MPS II. Particular focus is given to the multidisciplinary nature of patient management, which requires input from paediatricians, specialist nurses, otorhinolaryngologists, orthopaedic surgeons, ophthalmologists, cardiologists, pneumologists, anaesthesiologists, neurologists, physiotherapists, occupational therapists, speech therapists, psychologists, social workers, homecare companies and patient societies. TAKE-HOME MESSAGE: Expertise in recognising and treating patients with MPS II varies widely between countries. This article presents pan-European recommendations for the diagnosis and management of this life-limiting disease.