Neonatal diagnosis of Schwartz-Jampel syndrome with dramatic response to carbamazepine

Neonatal Schwartz-Jampel syndrome type II: a rare case of peripheral origin of neonatal hypertonia

Neonatal Schwartz-Jampel syndrome type II is a rare and severe form of genetic disorder. Different from the classical appearance in infancy, neonatal presentation involves respiratory and feeding difficulties, along with characteristic pursed appearance of the mouth, myotonia, skeletal dysplasia and severe fatal hyperthermia. The clinical spectrum of this syndrome is so wide that it easily baffles with more common differentials. In this case report, a neonate born to third-degree consanguineous marriage with previous two abortions presented with respiratory difficulty, severe hyperthermia and feeding difficulty, which were daunting challenges to manage due to being refractory to standard line of management. Severe myotonia and gross dysmorphism were challenging dots to connect. Targeted exome sequencing was a ray of hope, which revealed homozygous mutation in the leukaemia inhibitory factor receptor gene on chromosome 5p13, confirming the genetic diagnosis for a fairly common spectrum of symptoms. The neonate later developed pneumoperitoneum and succumbed to underlying severe neonatal illness.

The evolving therapeutic landscape of genetic skeletal disorders

BACKGROUND

Rare bone diseases account for 5% of all birth defects yet very few have personalised treatments. Developments in genetic diagnosis, molecular techniques and treatment technologies however, are leading to unparalleled therapeutic advance. This review explores the evolving therapeutic landscape of genetic skeletal disorders (GSDs); the key conditions and there key differentials.

METHODS

A retrospective literature based review was conducted in December 2018 using a systematic search strategy for relevant articles and trials in Pubmed and clinicaltrials.gov respectively. Over 140 articles and 80 trials were generated for review.

RESULTS

Over 20 personalised therapies are discussed in addition to several novel disease modifying treatments in over 25 GSDs. Treatments discussed are at different stages from preclinical studies to clinical trials and approved drugs, including; Burosumab for X-linked hypophosphatemia, Palovarotene for Hereditary Multiple Exostoses, Carbamazepine for Metaphyseal Chondrodysplasia (Schmid type), Lithium carbonate and anti-sclerostin therapy for Osteoporosis Pseudoglioma syndrome and novel therapies for Osteopetrosis. We also discuss therapeutic advances in Achondroplasia, Osteogenesis Imperfecta (OI), Hypophosphotasia (HPP), Fibrodysplasia Ossificans Progressiva, and RNA silencing therapies in preclinical studies for OI and HPP.

DISCUSSION

It is an exciting time for GSD therapies despite the challenges of drug development in rare diseases. In discussing emerging therapies, we explore novel approaches to drug development from drug repurposing to in-utero stem cell transplants. We highlight the improved understanding of bone pathophysiology, genetic pathways and challenges of developing gene therapies for GSDs.

Multidisciplinary approach to the treatment of a patient with chondrodystrophic myotonia (Schwartz-Jampel vel Aberfeld syndrome): case report and literature review

Chondrodystrophic myotonia, Schwartz-Jampel syndrome, is a rare congenital disorder, which results from disturbance in a perlecan protein synthesis. Most affected are the muscles, acting in generalized myotonia, leading to joint contractures, weird-looking mask-like face appearance, and causing vision disturbances. Also, impaired bones and cartilages result in skeletal anomalies and dental disorders. Allergic reactions to numerous drugs occur in affected individuals. Surgical treatment is risky, due to a low tolerance of anesthetics and high risk of malignant hyperthermia. In this article, a case of 17-year-old girl with Schwartz-Jampel syndrome is presented. The patient with typical syndrome debilitations underwent long diagnostic scheme and multiple treatments in order to restore acceptable appearance and function. All procedures were performed with cautious anesthesiologists' supervision. Modern diagnostic tools can improve the diagnosis rate while multidisciplinary evaluation and advanced treatment techniques can reveal symptoms, minimizing the hazard of anesthesia and improving the quality of life.

Botulinum toxin A injections for the treatment of Schwartz-Jampel syndrome: a case series

Schwartz-Jampel syndrome is a rare autosomal recessive disorder characterized by myotonia and skeletal dysplasia. Botulinum toxin A is emerging as a therapeutic option for patients with this syndrome. This study describes the use of botulinum toxin A in 4 children with Schwartz-Jampel syndrome. The response to this therapeutic modality was limited and variable.

Sporadic major hyperekplexia in neonates and infants: clinical manifestations and outcome

The aim of the present study is to report on the syndrome of sporadic major hyperekplexia during the neonatal period and early infancy, diagnosed in 39 patients at an average age of 3.3 months, the most severely affected during the first month of life. The patients mainly presented with marked irritability and recurrent startles in response to handling or even minute sounds, accompanied by rhythmic jerky movements and occasionally breath-holding episodes. Family history was negative for hyperekplexia, although eight parents reported jerky leg movements during sleep. The hallmark of hyperekplexia consisted of a hyper-alert gaze and an exaggerated startle with delayed habituation, also elicited by nose tapping and air blowing on the face accompanied by increasing rigidity. Nine severely affected infants, presenting with relentless startles, marked stiffness, violent rhythmic jerks, and breath-holding episodes were treated with oral low doses of clonazepam and completely recovered. Overall, the debilitating symptoms of hyperekplexia gradually resolved in all 39 infants, and their developmental assessment by 2 years of age was within the normal range. Therefore a prompt diagnosis of hyperekplexia during the neonatal period and early infancy, and then treatment if required with benzodiazepines to alleviate the debilitating symptoms, may prevent life-threatening events and enable better feeding and handling. Establishing the diagnosis of such a relatively benign disorder with a favorable developmental outcome may avoid unjustified extensive investigations or unnecessary treatment, suspecting an ominous progressive neurologic disorder.

Clinico-pathogenetic findings and management of chondrodystrophic myotonia (Schwartz-Jampel syndrome): a case report

BACKGROUND

Chondrodystrophic myotonia or Schwartz-Jampel syndrome is a rare genetic disorder characterized by myotonia and skeletal dysplasia. It may be progressive in nature. Recently, the gene responsible for Schwartz-Jampel syndrome has been found and the defective protein it encodes leads to abnormal cartilage development and anomalous neuromuscular activity.

CASE PRESENTATION

We report the clinical findings and the management of an 8-year-old boy with this disorder. The molecular findings confirm that the patient is a compound heterozygote with a different splicing mutation in each Perlecan allele. This resulted in a significant reduction in the production of the encoded normal protein.

CONCLUSION

We discuss the multi-disciplinary management of Schwartz-Jampel syndrome that will facilitate optimal care and timely intervention of patients with this disorder.

Schwartz-jampel syndrome: report of five cases

We describe five patients with Schwartz-Jampel syndrome (SJS) examined at the outpatient service for neuromuscular disorders at our Institution from 1996 to 1999 with the objective of emphasizing the characteristic dysmorphic phenotype of SJS and its different clinical forms. Two cases presented SJS-type 1A, two had SJS-type 1B and one manifested SJS-type 2. Two boys with 3 and 13 years of age had generalized stiffness and the characteristic facial as well as osteoarticular changes from birth. Other two boys with 11 and 7 years had less marked dysmorphic changes at birth and manifested myotonia, as a limiting factor, during the second year of age. A girl with two months of age had severe myotonia from birth leading to feeding diffuculties. In all cases the diagnosis was based on dysmorphic features, and on electromyographic changes showing continuous electrical activity of muscle fibers. All were treated with carbamazepine, 20-30 mg/Kg since diagnosis. The four boys (all with normal intelligence) improved of myotonia in daily activities, markedly in three, and moderately in one. The girl did not improve and showed global development delay: by the last follow-up (at 20 months of age) she did not sit unsupported, and had mental retardation. Carbamazepine in SJS-type 1 improves general daily performance and psychological status of the patients.