Identification of a novel compound heterozygote SCO2 mutation in cytochrome c oxidase deficient fatal infantile cardioencephalomyopathy

Fatal infantile cardioencephalomyopathy (OMIM No. 604377) is a disorder of the mitochondrial respiratory chain and is characterised by neonatal progressive muscular hypotonia and cardiomyopathy because of severe Cytochrome c oxidase deficiency. Here we report a novel mutation in the Cytochrome c oxidase assembly gene SCO2 in an infant with fatal infantile cardioencephalomyopathy despite normal initial metabolic screening. CONCLUSION: In newborns with unexplained muscular hypotonia and cardiomyopathy genetic testing of mitochondrial respiratory chain disorders might be helpful to establish a final diagnosis and guide treatment decisions.     

Congenital muscular dystrophy with laminin-a2 deficiency in early infancy: diagnosis and long-term follow-up

Congenital muscular dystrophy (CMD) is a heterogeneous group of neuromuscular disorders characterized by muscle weakness and hypotonia at birth or within the first few months of life. It is inherited in an autosomal recessive pattern. About half of the patients have a deficiency of the alpha-2-chain of laminin (merosin). We describe a case of congenital muscular dystrophy in an infant with laminin-a2-chain deficiency, which appeared hypotonia in early infancy. Diagnosis was made by clinical features and the histological and immunohistochemical studies on muscle biopsy.     

L’amyotrophie spinale infantile : cause fréquente des hypotonies congénitales au Maroc

Introduction

Congenital hypotonia is a non specific symptom frequently seen in newborns and infants, and whose etiological diagnosis is often difficult due to the lack of specialized and affordable explorations. Childhood-onset proximal spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by degeneration of the anterior horn cells of the spinal cord, leading to progressive paralysis with muscular atrophy. In more than 95% of the cases, it results from deletion of exon 7 of the SMN gene localized on 5q13, easily identified by molecular biology.

Objective

To determine the prevalence of the deletion of exon 7 of the SMN gene in congenital hypotonia with an unknown cause in Morocco.

Patients and methods

We investigated the deletion of exon 7 of the SMN gene in 87 newborns and infants with congenital hypotonia. The cause of congenital hypotonia could not be determined in 60 of them, while 27 had electrophysiological evidence for an involvement of the anterior horn cells.

Results

The homozygous deletion of the SMN gene was detected in 23 of the newborns with unknown cause for hypotonia (38%) and in 21 of the infants whose electromyogram suggested infantile spinal amyotrophy (78%).

Conclusion

This study underlines the advantages of a systematic search for the deletion of exon 7 of the SMN gene in every infant suffering from congenital hypotonia due to an unknown cause, particularly when the child's vital prognosis is at stake. This genetic test, easily implemented, should be systematically proposed after an attentive clinical evaluation in countries where the etiological diagnosis of congenital hypotonia is not systematic.     

Atypical phenylketonuria due to biopterin deficiency. Early treatment with tetrahydrobiopterin and neurotransmitter precursors, trials of monotherapy

This report presents the first case where an infant with tetrahydrobiopterin deficiency has been identified by screening of newborns with hyperphenylalaninemia for tetrahydrobiopterin deficiency. Therapy with L-Dopa, 5-hydroxytryptophan, Carbidopa and tetrahydrobiopterin was started at the age of seven weeks while the child received a normal diet. At that time already muscular hypotonia was observed. The girl, now 2 1/2 years old, shows slight muscular hypotonia and hypomotility, short periods of hypertonic extension of the limbs, and retardation of sensomotor and mental development of about 6-8 months. Monotherapy with tetrahydrobiopterin dihydrochloride, 20-40 mg/kg b.w., diminished the muscular hypotonia. The effect lasted however for only about 1 day. While urinary serotonin and phenylalanine remained normal for at least 3 days and neopterin was only slightly elevated, urinary free dopamine however remained low. Similar results were obtained after 1',2'-diacetyl tetrahydrobiopterin dihydrochloride administration, 20 mg/kg b.w.     

Micromelic type of spondylo-meta-epiphyseal dysplasia (author's transl)

A 3 6/12 years old girl with micromelic type of spondylo-meta-epiphyseal dysplasia combined with hepatosplenomegaly and muscular hypotonia is described.     

儿童脊肌萎缩症23例临床特点及遗传学分析

目的 探讨脊肌萎缩症的临床特点和遗传方式。方法 对23例脊肌萎缩症患儿的临床资料进行总结,并用Weiber先证法分析其发病的遗传规律。结果 临床特点为出生后双下肢呈对称性弛缓性瘫痪且进行性加重,四肢近端无力,肌张力、肌力低下;肌电图主要表现为神经原性损害。隐性遗传分离分析表明,12个家系23例患儿发病方式符合常染色体隐性遗传。结论 脊肌萎缩症的临床发病早且病死率高,在遗传咨询中注意作相关产前基因检查,可避免该类患儿的出生。     

Diagnostic approach to neonatal hypotonia: retrospective study on 144 neonates

The objectives of our study were to determine the actual frequency of the different disorders causing neonatal hypotonia and to assess the reliability of the first physical examination as well as the contribution of the main standard diagnostic tests. One hundred and forty-four infants diagnosed with neonatal hypotonia between January 1st 1999 and June 30th 2005 in our tertiary care facility were retrospectively included in the study. Perinatal history, clinical type of hypotonia, results of standard diagnostic tests, final diagnosis and outcome were abstracted from the original charts. A final diagnosis was reached in 120 cases. Central (cerebral) causes represented 82% of the elucidated cases, mostly hypoxic and hemorrhagic lesions of the brain (34%), chromosomal aberrations and syndromic disorders (26%) and brain malformations (12%). Peripheral (neuromuscular) causes were mainly represented by spinal muscular atrophy (6%) and myotonic dystrophy (4%). Positive predictive value of the initial clinical examination was higher in central type hypotonia. Neuroimaging, karyotype analysis and DNA-based tests were the most helpful diagnostic tools. These recent clinical data can be used to improve our strategy in investigating neonatal hypotonia and a diagnostic algorithm is proposed based on our findings.     

The use of invasive ventilation is appropriate in children with genetically proven spinal muscular atrophy type 1: the motion against

Spinal muscular atrophy (SMA) is a relatively common, profoundly disabling and incurable disease that presents in early childhood with hypotonia, weakness and decreased movement. Without ventilatory support, premature death from respiratory insufficiency is universal in children with spinal muscular atrophy type 1 (SMA1). With mechanical ventilation, however, long-term survival in SMA1 has been reported from numerous international centres. Children kept alive by this means experience progressive paralysis and eventually become effectively 'locked in' on the ventilator, with no useful movements of the extremities, progressive facial and bulbar weakness, and complete inability to communicate. Prolongation of life by invasive ventilation in such cases is futile given the absence of curative treatments for infants with SMA1, and overly burdensome given the unacceptable quality of life of such children.     

Hypercalcaemia in infancy; a presenting feature of spinal muscular atrophy

A 10 month old girl presented with a history of constipation from early life. She was found to be hypercalcaemic with hypercalciuria and nephrocalcinosis. Her mild motor delay and hypotonia were thought to be linked to chronic hypercalcaemia, but when these features failed to improve despite normocalcaemia on a low calcium diet the possibility of neuromuscular disease was explored in more detail. She was subsequently found to have spinal muscular atrophy type 2. We suspect that the hypercalcaemia with hypercalciuria observed in this case reflects altered bone turnover secondary to reduced muscular activity.     

Hypercalcaemia in infancy; a presenting feature of spinal muscular atrophy.

A 10 month old girl presented with a history of constipation from early life. She was found to be hypercalcaemic with hypercalciuria and nephrocalcinosis. Her mild motor delay and hypotonia were thought to be linked to chronic hypercalcaemia, but when these features failed to improve despite normocalcaemia on a low calcium diet the possibility of neuromuscular disease was explored in more detail. She was subsequently found to have spinal muscular atrophy type 2. We suspect that the hypercalcaemia with hypercalciuria observed in this case reflects altered bone turnover secondary to reduced muscular activity.     

An unusual cause of failure of weaning from mechanical ventilation in an infant

The weaning process is a critical phase in patients undergoing mechanical ventilation. This process can be hampered by numerous causes, such as neuromuscular diseases and spinal muscular atrophy (SMA). We present a 6-month-old boy with respiratory distress, fever, marked hypotonia without motor developmental milestones, and areflexia. The patient showed progressive respiratory distress requiring mechanical ventilation. Definitive weaning was not achieved and the boy died from respiratory failure. Partial autopsy was performed with a diagnosis of SMA and genetic study of the parents. Neuromuscular diseases are an infrequent cause of respiratory insufficiency in suckling infants. The differential diagnosis is made between axonal and motor neuron diseases. The diagnosis was confirmed by muscular biopsy and genetic study.     

A case of Walker-Warburg syndrome resulting from a homozygous POMT1 mutation.

Walker--Warburg syndrome (WWS), the most severe alpha-dystroglycanopathy, is characterized by brain and eye anomalies, and congenital muscular dystrophy (CMD). So far at least four genes (POMT1, POMT2, Fukutin, and FKRP gene) have been implicated in WWS, accounting for about 30% of all cases. We report a male patient with WWS resulting from a homozygous nonsense mutation (R514X) in the POMT1 gene. The patient had congenital hydrocephalus which was detected at 29 weeks of gestation. A brain MRI obtained after birth revealed type II lissencephaly, hydrocephalus, and pontocerebellar hypoplasia. The case also exhibited severe ocular malformations and muscular hypotonia due to CMD.     

Heart Transplantation for Barth Syndrome

Barth syndrome is an X-linked recessive disorder comprising dilated cardiomyopathy, muscular hypotonia, and cyclical neutropenia. Affected children usually die during infancy as a consequence of septicemia, cardiac failure, or both. We report a patient with Barth syndrome who underwent successful heart transplantation.     

Diaphragmatic spinal muscular atrophy with bulbar weakness.

We present the clinical and histopathological features of a child affected by diaphragmatic spinal muscular atrophy. The child was born with mild distal arthrogryposis, mild hypotonia and developed marked diaphragmatic and bulbar muscle weakness in the first week of life. Electrophysiological and pathological investigations performed at presentation were not conclusive, while the investigations performed at 3 months showed a clear neurogenic picture. Genetic studies excluded involvement of the SMN gene, or of other genes located on chromosome 5q, confirming that this syndrome represents a different entity from typical proximal spinal muscular atrophy.     

Syndrome of retarded growth,obesity, muscular hypotonia and mental retardation (Prader-Willi syndrome)

Summary A 1 1/2-year-old male child with the Prader-Willi syndrome (retarded growth, obesity, muscular hypotonia and mental retardation) has been described. From the department of Pediatrics, College of Medical Sciences, Banaras Hindu University, Varanasi-5.     

X-linked infantile spinal muscular atrophy

Four male infants from three sibships in an extended family were noted to have hypotonia, areflexia, and congenital joint contractures. The findings of electromyography and muscle histology were consistent with infantile spinal muscular atrophy (SMA). Pedigree analysis suggests that this disorder represents an X-linked, recessive form of SMA. Findings in similar kindreds may explain the previously reported increased male-female ratio in infantile SMA.     

A new case of short-chain acyl-CoA dehydrogenase deficiency with isolated ethylmalonic aciduria

A 28-month-old Turkish girl presented with recurrent bronchopneumonia and severe muscular hypotonia. Urinary excretion of ethylmalonic acid was persistently elevated, methylsuccinate appearing only in stress situations. Studies in cultured fibroblasts showed a deficiency of short-chain acyl-CoA dehydrogenase.     

Ehlers-Danlos Syndrome Type VI in a 17-Year-Old Iranian Boy with Severe Muscular Weakness – A Diagnostic Challenge?

Background

The Ehlers-Danlos syndrome type VI (EDSVI) is an autosomal recessive connective tissue disease which is characterized by severe hypotonia at birth, progressive kyphoscoliosis, skin hyperelasticity and fragility, joint hypermobility and (sub-)luxations, microcornea, rupture of arteries and the eye globe, and osteopenia. The enzyme collagen lysyl hydroxylase (LH1) is deficient in these patients due to mutations in the PLOD1 gene.

Case Presentation

We report a 17-year-old boy, born to related parents, with severe kyphoscoliosis, scar formation, joint hypermobility and multiple dislocations, muscular weakness, rupture of an ocular globe, and a history of severe infantile hypotonia. EDS VI was suspected clinically and confirmed by an elevated ratio of urinary total lysyl pyridinoline to hydroxylysyl pyridinoline, abnormal electrophoretic mobility of the α-collagen chains, and mutation analysis.

Conclusion

Because of the high rate of consanguineous marriages in Iran and, as a consequence thereof, an increased rate of autosomal recessive disorders, we urge physicians to consider EDS VI in the differential diagnosis of severe infantile hypotonia and muscular weakness, a disorder which can easily be confirmed by the analysis of urinary pyridinolines that is highly specific, sensitive, robust, fast, non-invasive, and inexpensive.     

Konnataler Stridor, muskul?re Hypotonie und Hydrocephalus occlusus

The case of a male infant with congenital stridor, retardation of motor function due to muscular hypotonia and development of hydrocephalus is presented. MR imaging revealed a Chiari type I malformation. The hydrocephalus was successfully treated by endoscopic third ventriculostomy. The case illustrates the occasionally complex symptomatology and diagnostic challenges of Chiari type I malformation.     

Alpha-Thalassämie-Retardierungs-Syndrom

Alpha-thalassemia X-linked mental retardation (ATRX, MIM#301040) syndrome is associated with severe mental retardation, muscular hypotonia, facial dysmorphism, and genital anomalies in males. We present the case of a family with two affected boys. The diagnosis was made by maternal X-chromosome inactivation studies which showed marked skewing of maternal X-chromosome inactivation and ATRX analysis revealed a novel mutation in exon 34.