Clinical and genetic findings in five female patients with haemophilia A: Identification of a novel missense mutation, p.Phe2127Ser

Severe manifestations of X-linked recessive disorders such as haemophilia A (HA) are rare in females. Here we describe the clinical and genetic findings in five female HA patients from two different Spanish families. Three sisters born to consanguineous parents presented moderate bleeding due to a known mutation (p.Ser1791Pro) detected in a homozygous state. In the second family, two sisters with Morris syndrome (46,XY) and mild/moderate illness were hemizygous for a novel missense mutation, p.Phe2127Ser. The mutation is predicted to impair binding to the factor VIII (FVIII) carrier protein, von Willebrand factor, and thus increased clearance of FVIII from plasma. Clinical and molecular characterisation of these patients is essential to optimise follow-up, genetic counselling and treatment of the disease.

Nusinersen versus Sham Control in Infantile-Onset Spinal Muscular Atrophy

BACKGROUND

Spinal muscular atrophy is an autosomal recessive neuromuscular disorder that is caused by an insufficient level of survival motor neuron (SMN) protein. Nusinersen is an antisense oligonucleotide drug that modifies pre-messenger RNA splicing of the SMN2 gene and thus promotes increased production of full-length SMN protein.

METHODS

We conducted a randomized, double-blind, sham-controlled, phase 3 efficacy and safety trial of nusinersen in infants with spinal muscular atrophy. The primary end points were a motor-milestone response (defined according to results on the Hammersmith Infant Neurological Examination) and event-free survival (time to death or the use of permanent assisted ventilation). Secondary end points included overall survival and subgroup analyses of event-free survival according to disease duration at screening. Only the first primary end point was tested in a prespecified interim analysis. To control the overall type I error rate at 0.05, a hierarchical testing strategy was used for the second primary end point and the secondary end points in the final analysis.

RESULTS

In the interim analysis, a significantly higher percentage of infants in the nusinersen group than in the control group had a motor-milestone response (21 of 51 infants [41%] vs. 0 of 27 [0%], P<0.001), and this result prompted early termination of the trial. In the final analysis, a significantly higher percentage of infants in the nusinersen group than in the control group had a motor-milestone response (37 of 73 infants [51%] vs. 0 of 37 [0%]), and the likelihood of event-free survival was higher in the nusinersen group than in the control group (hazard ratio for death or the use of permanent assisted ventilation, 0.53; P=0.005). The likelihood of overall survival was higher in the nusinersen group than in the control group (hazard ratio for death, 0.37; P=0.004), and infants with a shorter disease duration at screening were more likely than those with a longer disease duration to benefit from nusinersen. The incidence and severity of adverse events were similar in the two groups.

CONCLUSIONS

Among infants with spinal muscular atrophy, those who received nusinersen were more likely to be alive and have improvements in motor function than those in the control group. Early treatment may be necessary to maximize the benefit of the drug. (Funded by Biogen and Ionis Pharmaceuticals; ENDEAR ClinicalTrials.gov number, NCT02193074 .).

[Comparative genomic hybridisation as a first option in genetic diagnosis: 1,000 cases and a cost-benefit analysis]

BACKGROUND AND OBJECTIVE

Conventional cytogenetics diagnoses 3-5% of patients with unexplained developmental delay/intellectual disability and/or multiple congenital anomalies. The Multiplex Ligation-dependent Probe Amplification increases diagnostic rates from between 2.4 to 5.8%. Currently the comparative genomic hybridisation array or aCGH is the highest performing diagnostic tool in patients with developmental delay/intellectual disability, congenital anomalies and autism spectrum disorders. Our aim is to evaluate the efficiency of the use of aCGH as first-line test in these and other indications (epilepsy, short stature).

PATIENTS AND METHOD

A total of 1000 patients referred due to one or more of the abovementioned disorders were analysed by aCGH.

RESULTS

Pathogenic genomic imbalances were detected in 14% of the cases, with a variable distribution of diagnosis according to the phenotypes: 18.9% of patients with developmental delay/intellectual disability; 13.7% of multiple congenital anomalies, 9.76% of psychiatric pathologies, 7.02% of patients with epilepsy, and 13.3% of patients with short stature. Within the multiple congenital anomalies, central nervous system abnormalities and congenital heart diseases accounted for 14.9% and 10.6% of diagnoses, respectively. Among the psychiatric disorders, patients with autism spectrum disorders accounted for 8.9% of the diagnoses.

CONCLUSIONS

Our results demonstrate the effectiveness and efficiency of the use of aCGH as the first line test in genetic diagnosis of patients suspected of genomic imbalances, supporting its inclusion within the National Health System.

Social/economic costs and health-related quality of life in patients with spinal muscular atrophy (SMA) in Spain

BACKGROUND

The aim of this study was to determine the economic burden and health-related quality of life (HRQOL) of patients with Spinal Muscular Atrophy (SMA) and their caregivers in Spain.

METHODS

This was a cross-sectional and retrospective study of patients diagnosed with SMA in Spain. We adopted a bottom up, prevalence approach design to study patients with SMA. The patient's caregivers completed an anonymous questionnaire regarding their socio-demographic characteristics, use of healthcare services and non-healthcare services. Costs were estimated from a societal perspective (including healthcare costs and non-healthcare costs), and health-related quality of life (HRQOL) was assessed using the EQ-5D questionnaire. The main caregivers also answered a questionnaire on their characteristics and on their HRQOL.

RESULTS

A total of 81 caregivers of patients with different subtypes of SMA completed the questionnaire. Based on the reference unitary prices for 2014, the average annual costs per patient were € 33,721. Direct healthcare costs were € 10,882 (representing around 32.3% of the total cost) and the direct non-healthcare costs were € 22,839 (67.7% of the total cost). The mean EQ-5D social tariff score for patients was 0.16, and the mean score of the EQ-5D visual analogue scale was 54. The mean EQ-5D social tariff score for caregivers was 0.49 and their mean score on the EQ-5D visual analogue scale was 69.

CONCLUSION

The results highlight the burden that SMA has in terms of costs and decreased HRQOL, not only for patients but also for their caregivers. In particular, the substantial social/economic burden is mostly attributable to the high direct non-healthcare costs.

Discordant Genotypic Sex and Phenotype Variations in Two Spanish Siblings with 17α-Hydroxylase/17,20-Lyase Deficiency Carrying the Most Prevalent Mutated CYP17A1 Alleles of Brazilian Patients

17α-hydroxylase/17,20-lyase deficiency is a rare form of congenital adrenal hyperplasia caused by mutations in CYP17A1. Two phenotypic female sisters, aged 17 and 15 years and with 46,XY and 46,XX karyotypes, respectively, presented with primary amenorrhea and absent secondary sexual characteristics. The elder sib also presented with high blood pressure. Both patients had elevated levels of ACTH, gonadotropins, progesterone, corticosterone, and deoxycorticosterone, and reduced levels of estradiol, testosterone, androstenedione, 17-OH-P, DHEA-S, cortisol, aldosterone, and renin activity. The CYP17A1 gene was sequenced, and polymorphic haplotypes were further analyzed in the Spanish family and in Brazilian patients. The 2 sisters were compound heterozygous for p.Arg362Cys and p.Trp406Arg mutations, previously described as the most prevalent mutations in Brazilian families of Spanish (p.Trp406Arg) or Portuguese (p.Arg362Cys) origin. Analysis of polymorphisms in CYP17A1 suggested that the paternal allele with p.Arg362Cys may share a common origin with the Brazilian carriers, while the maternal allele with p.Trp406Arg did not. Hydrocortisone and sex hormone replacement therapy was initiated in both patients. In conclusion, one CYP17A1 mutation (p.Arg362Cys) may share a common ancestry in Brazilian and our present Spanish patients, while p.Trp406Arg may have arisen separately. The elder patient (46,XY) developed a more severe phenotype and a poorer response to estradiol replacement therapy.

Genotype-phenotype correlation of SMN locus genes in spinal muscular atrophy children from Argentina

BACKGROUND/PURPOSE

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder, considered one of the leading causes of infant mortality. It is caused by mutations in the SMN1 gene. A highly homologous copy of this gene named SMN2 and other neighbouring genes, SERF1A and NAIP, are considered phenotypic modifiers of the disease. In recent years, notable advances have been made in SMA research regarding evaluation, prognosis, and therapeutic options. Thus, genotype-phenotype studies in SMA are important to stratify patients for motor function tests and for envisaged clinical trials. The aim of this study was to provide clinical and molecular data of a series of Argentinean children with SMA to establish a comprehensive genotype-phenotype correlation.

METHODS

144 Argentinean children with SMA (56 children with type I, 58 with type II, and 30 with type III) were evaluated. The copy number of SMN2, SERF1A, and NAIP genes was established using MLPA (Multiplex Ligation-dependent Probe Amplification) and then correlated with the patients clinical subtypes. To improve clinical characterization we considered the initial symptoms that prompted the consultation, age of acquisition of motor abilities to independent walking and age at loss of gait. We also evaluated clinical and molecular features of sibling pairs in seven families.

RESULTS

A strong correlation was observed between the SMN2 copy number and SMA phenotype while SERF1A and NAIP copy number showed a moderate correlation. We observed intra- and inter-family differences among the SMA types.

CONCLUSION

This first genotype-phenotype correlation study in Argentinean SMA children provides data to improve patient stratification and define more adequate follow-up parameters.

A Novel Recurrent Breakpoint Responsible for Rearrangements in the Williams-Beuren Region

Copy number variants (CNVs) of the Williams-Beuren syndrome (WBS) 7q11.23 region are responsible for neurodevelopmental disorders with multisystem involvement and variable expressivity. We found 2 patients with a deletion and 1 patient with a duplication in this region sharing a common breakpoint located between the LIMK1 and EIF4H(WBSCR1) genes. One patient had a WBS phenotype, although testing with a commercially available FISH assay was negative for the deletion. A further test using array CGH showed an atypical WBS region deletion. The second patient showed global developmental delay, speech delay and poor motor skills with a deletion outside the WBS region. The third patient had manifestations compatible with an autism spectrum disorder showing a duplication in the WBS region. Our findings point to the existence of a previously unrecognized recurrent breakpoint responsible for rearrangements in the WBS region. Given that most commercial FISH assays include probes flanking this novel breakpoint, further testing with array CGH should be performed in patients with WBS and negative FISH results.

Mapping the differences in care for 5,000 spinal muscular atrophy patients, a survey of 24 national registries in North America, Australasia and Europe

Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder characterised by the degeneration of motor neurons and progressive muscle weakness. It is caused by homozygous deletions in the survival motor neuron gene on chromosome 5. SMA shows a wide range of clinical severity, with SMA type I patients often dying before 2 years of age, whereas type III patients experience less severe clinical manifestations and can have a normal life span. Here, we describe the design, setup and utilisation of the TREAT-NMD national SMA patient registries characterised by a small, but fully standardised set of registry items and by genetic confirmation in all patients. We analyse a selection of clinical items from the SMA registries in order to provide a snapshot of the clinical data stratified by SMA subtype, and compare these results with published recommendations on standards of care. Our study included 5,068 SMA patients in 25 countries. A total of 615 patients were ventilated, either invasively (178) or non-invasively (437), 439 received tube feeding and 455 had had scoliosis surgery. Some of these interventions were not available to patients in all countries, but differences were also noted among high-income countries with comparable wealth and health care systems. This study provides the basis for further research, such as quality of life in ventilated SMA patients, and will inform clinical trial planning.

[Hammersmith functional rating scale for children with spinal muscular atrophy. Validation of the Spanish version]

AIMS

This study was conducted with the aim of developing the Spanish version of the Hammersmith functional rating scale for children with spinal muscular atrophy (SMA), to establish the interobserver reliability and to adapt it to Spanish children with SMA types II and III.

PATIENTS AND METHODS

We assessed 31 children with a mean age of 4.7 years (range: 2.5-9 years) and they were re-assessed at 3, 6 and 12 months. The children with SMA type II could not walk and the children with SMA type III were able to walk.

RESULTS

Interobserver reliability was 95%. The median of the score in the group with SMA type II was 17 (range: 0-34) and in the SMA type III group it was 39 (range: 37-40). The results of the group with SMA type II at 12 months were poorer, although not to a statistically significant extent, which suggested that the disease was getting worse.

CONCLUSIONS

The Spanish version presents a high degree of interobserver reliability, is easy to administer in clinical practice and is a good tool for assessing the severity of the disease in patients with SMA, above all in those who are unable to walk.

Absence of large intragenic rearrangements in the DPYD gene in a large cohort of colorectal cancer patients treated with 5-FU-based chemotherapy

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT * Dihydropyrimidine dehydrogenase (DPD) is the enzyme responsible for the elimination of approximately 80% of the administered dose of 5-fluorouracil (5-FU). * Mutations in the DPD-coding gene have been shown to increase the risk of severe toxicity in 5-FU treated patients. * The IVS14+1G>A is the most common DPYD mutation. WHAT THIS STUDY ADDS * The intragenic rearrangements of DPYD using multiplex ligation-dependent probe amplification (MLPA) were studied for the first time in a large series of 234 colorectal cancer patients treated with 5-FU-containing chemotherapy. * No deletions or duplications of one or more DPYD exons were detected. The presence of the IVS14+1G>A mutation was also excluded. * These data show that neither the large genomic rearrangements in the DPYD gene nor the IVS14+1G>A mutation are responsible for the serious toxicity associated with a 5-FU containing regimen in this cohort of Spanish patients. AIMS To study the relationship between the toxicity associated with a 5-FU-based therapy and the presence of (i) the large intragenic rearrangements in the DPYD gene and (ii) the IVS14+1G>A mutation. METHODS We used the multiplex ligation-dependent probe amplification technique (MLPA) to study genomic DNA from 234 colorectal cancer patients treated with 5-FU-based chemotherapy. RESULTS We did not detect any deletion/duplication in the DPYD gene. The presence of the IVS14+1G>A mutation was also excluded. CONCLUSIONS Neither the large genomic rearrangements in the DPYD gene nor the IVS14+1G>A mutation play a significant role in the development of serious toxicity associated with a 5-FU containing regimen.

Measurement of muscle strength with a handheld dynamometer in patients with chronic spinal muscular atrophy

OBJECTIVE

To measure muscle strength in patients with spinal muscular atrophy using a handheld dynamometer as an objective tool to evaluate the progression of disease and the outcome of therapeutic trials.

DESIGN

Maximum voluntary isometric contraction was measured in a group of 24 patients aged 5-38 years with types II and III spinal muscular atrophy. Four muscle groups were examined. Data were grouped according to age and sex. Comparison was made between spinal muscular atrophy types; ambulatory vs non-ambulatory, and survival motor neuron (SMN)2 copies. The results were compared with those of a healthy reference population.

RESULTS

Muscle strength was much lower in patients with spinal muscular atrophy than in the healthy population. The walkers group yielded higher values than patients who were non-walkers. Knee extensors were the weakest muscles in both groups, regardless of the ability to walk. The greatest differences were found between ambulatory and non-ambulatory patients. Non-walkers type III patients showed lower values, similar to those for type II patients. Patients with 3 and 4 SMN2 copies showed higher strength with respect to those with 2 SMN2 copies, although not statistically significant.

CONCLUSION

The handheld dynamometer is a valid tool for measuring muscle strength in patients with spinal muscular atrophy. It can be used to measure disease progression and to evaluate changes in therapeutic trials.

Spinal muscular atrophy during human development: where are the early pathogenic findings?

Spinal muscular atrophy (SMA) is an autosomal recessive disorder that affects motor neurons. It is caused by mutations in the survival motor neuron gene 1 (SMN1). The SMN2 gene, which is the highly homologous SMN1 copy that is present in all patients, is unable to prevent the disease. SMA patients can be classified into four groups based on age at onset and acquired milestones (type I or severe acute disease, with onset before 6 months; type II, before 18 months; type III, after 18 months and type IV, in adult life). The human developmental period is believed to play an essential role in SMA pathogenesis. However, the neuropathologic study of SMA comes largely from postnatal necropsy samples, which describe the end-stage of the disease. With the exception of severe congenital SMA (or Type 0 SMA), type I patients tend to present a short but variable presymptomatic period after birth. Our main interest lies in studying SMA during human development so as to gain insight into the mechanism of the disease in the prenatal-presymptomatic stage. In fetuses of 12-15 weeks' gestational age we systematically studied histology, cell death and gene expression in spinal cord and muscle, the key tissues involved in the disease. Furthermore, ultrasound parameters were investigated at these stages. These studies may help to delineate an early intervention in SMA, in particular during the potential therapeutic window.

Utility of a (GT)n dinucleotide repeat in intron 1 of the factor 8 gene for haemophilia A carrier diagnosis

We report the usefulness of a dinucleotide GT repeat in intron 1 of the factor 8 gene in carrier diagnosis of haemophilia A (HA). We analyzed 47 women from HA families in which the mutation was not identified in the index case and in which the common intragenic polymorphic markers were uninformative. The intron 1 GT repeat was useful to identify the X chromosome with the mutation in 19 of them. The analysis of this easily detectable marker in conjunction with other current markers may facilitate X chromosome identification in a large proportion of HA families.

Prenatal diagnosis for risk of spinal muscular atrophy

OBJECTIVES

Prenatal diagnosis of spinal muscular atrophy is usually performed in high risk couples by detection of a homozygous deletion in the survival motor neurone gene (SMN1). However, other relatives at risk of being carriers very often request genetic counselling and the possibility of prenatal diagnosis. The aim of this study was to validate a SMN1 gene quantitative test to help the couples formed by one spinal muscular atrophy carrier and a partner of the general population (1/200 potential risk) to achieve a less ambiguous risk result for the pregnancy.

DESIGN

Spinal muscular atrophy carrier studies in at-risk individuals.

SETTING

Department of Genetics and Gynaecology and Obstetrics in a large university hospital.

POPULATION

Seventy-nine obligate carriers (more than one affected child with deletion in the offspring) and 58 non-carriers (relatives of spinal muscular atrophy families defined by marker studies) were tested to set up a quantitative analysis. The method was applied in different situations in 126 members from 34 families with spinal muscular atrophy patients.

METHODS

DNA studies of the SMNI gene by marker analysis and quantitative assay.

MAIN OUTCOME MEASURES

To determine double (non-carrier) or single dose (carrier) of exon 7 of the SMN1 gene in relatives of spinal muscular atrophy patients. Bayesian calculation of risk.

RESULTS

The sensitivity and specificity of the method were 96% and 100%, respectively. Studies on different couples with an a priori risk of 1/200 allowed us to reduce the final risk to 1/5000 or to increase it to 1/4.

CONCLUSIONS

The quantitative method can be used to achieve a less ambiguous risk in pregnancies with a 1/200 risk and in families where no sample is available to study the index case. Screening of gamete donors when the recipient is a known carrier should also be considered.

[Molecular basis of spinal muscular atrophy: th SMN gene]

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by degeneration and loss of motor neurons of the anterior horn of the spinal cord. The clinical manifestations include proximal symmetric weakness and progressive atrophy of muscle. SMA is classified by age of onset, severity of symptoms, and evolution in three groups: type I, severe or Werdnig-Hoffmann disease, type II or intermediate and type III, moderate-mild, Kugelberg-Welander disease. The identification of the SMN1 gene as determinant of SMA opened new alternatives to study the disease. Most of the patients have deletions and conversion of SMN1 and in a small number of cases, point mutations were detected. There is no obvious genotype-phenotype correlation because homozygous absence of SMN1 was associated to a wide spectrum of manifestations from congenital disease to non symptomatic cases. Modifier factors, such as the number of copies of SMN2, could influence the phenotype. Other possible modifier genes are under study. The SMN gene is expressed in various neuronal populations. However, only motor neurons are responsible for the manifestations of the disease. The SMN protein is part of a complex with various proteins involved in the splicing reaction. This apparent essential function for all cells could be critical in motor neurons. When SMN1 is absent or dysfunctional, the motor neurons could be more sensitive because they have an increased transcription activity. In this situation, other cells and tissues could be protected by genetic or cellular factors still undiscovered.