|Year : 2016 | Volume
| Issue : 2 | Page : 290-291
Schwartz–jampel syndrome: Clinical and diagnostic phenotype of a rare genetic disorder
Bhaskara P Shelley1, US Vinayaka2
1 Department of Neurology, Yenepoya Medical College, Mangalore, Karnataka, India
2 Department of Radiodiagnosis, Yenepoya Medical College, Mangalore, Karnataka, India
|Date of Web Publication||20-Dec-2016|
Bhaskara P Shelley
Department of Neurology, Yenepoya Medical College, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
The distinctive phenotypic, clinical, skeletal characteristics with the typical electrophysiological features of an 11-year-old male child who presented to the neurology outpatient service are described, with the objective of emphasizing the diagnostic awareness of chondrodystrophic myotonia or Schwartz–Jampel syndrome, a very rare genetic disorder. This autosomal recessive disorder due to mutations in the gene Perlecan leads to abnormal cartilage development and anomalous neuromuscular activity.
Keywords: Chondrodystrophic myotonia, chondrodystrophy, dwarfism, myotonic myopathy
|How to cite this article:|
Shelley BP, Vinayaka U S. Schwartz–jampel syndrome: Clinical and diagnostic phenotype of a rare genetic disorder. Arch Med Health Sci 2016;4:290-1
An 11-year-old male child presented with distinctive facial and musculoskeletal features, hypertrophy of muscles of arms, trunk, abdomen, and legs, with pronounced muscle stiffness and mild generalized weakness. He was born to healthy nonconsanguineous parents. His mother recalled that quickening was observed at 6 months and felt less fetal movements when compared to her second pregnancy. Parents noted that he had achieved head control by 4 months, rolled over at 8 months, crawled at 9 months, and started walking without support by 18 months. At 18 months, he was noted to have an “athletic” physique with prominent “muscle bulges” with hypertrophy of muscles of upper and lower extremities, abdomen, paraspinal regions, and calves. At the age of 3 years, he started experiencing early morning stiffness of muscles, difficulty in opening eyelids, and difficulty in walking with awkward positioning of his legs and feet. At the age of 6 years, these symptoms aggravated remarkably with generalized muscle stiffness, difficulty in releasing his hand grip from objects he holds, has to open the eyelids with his fingers at times, experienced mild muscle weakness with difficulty in walking, running, climbing stairs, getting up from squatting position when compared to his normal younger brother. The stiffness was maximum at the onset of exercise, and his muscles loosened up after some time. He noticed cold sensitivity for his muscular symptoms and preferred bathing in hot water. There was no family history of neuromuscular disorders or skeletal dysplasias. He was intelligent, attending normal school and did not report cardiac symptoms. His height was 115 cm with a weight of 19 kg. He had intelligence quotient of 70.
Examination revealed diagnostic features such as a short stature, dysmorphic facies, fixed facial expression, pursed lips, microstomia micrognathia, low-set ears, short neck, and pes planus [Figure 1]. He had diffuse muscular hypertrophy and stiffness with eyelid myotonia, tongue myotonia, percussion myotonia at thenar eminence [Figure 2] and forearm muscles. Muscle strength testing revealed Grade 5 muscle power, difficult to elicit deep tendon reflexes, and had a crouching stance and a stiff gait. All muscles were in a state of contraction giving an appearance of hypertrophied muscles. Systemic examination proved unremarkable. Muscles enzymes, thyroid profile, electrocardiogram, and echocardiogram were normal. Skeletal survey revealed platybasia, relative shortening of 4th metatarsal bone bilaterally, bilateral canoe (oar)-shaped ribs, square shaped ilium, and a few bullet shaped vertebral bodies in the lower lumbar level with anterior beaking all of which were consistent with spondyloepiphyseal dysplasia [Figure 2]. Nerve conduction studies were normal. Electromyogram showed prolonged and persistent repetitive discharges, high-frequency discharges which did not wax and wane, with a few discharges having a dive-bomber sound, with normal motor units. His clinical phenotype described above in addition to the skeletal dysplasia features and coupled with electrophysiological myotonia did correspond to the diagnosis of Schwartz-Jampel syndrome (SJS) Type 1A. Chondrodystrophic myotonia or SJS is a rare autosomal recessive disorder that was described for the first time in 1951 and then better defined in 1962 by Schwartz and Jampel. It is a very rare inherited disease with <100 cases described so far where the diagnosis is made primarily by recognition of the clinical phenotype. The genetic defect results in abnormal cartilage development and anomalous neuromuscular activity due to mutations in the gene Perlecan (heparan sulfate proteoglycan 2 [HSPG2]) encoding the protein HSPG2 located in 1p34-p35.1. Prenatal diagnosis is possible in parents with affected sibs. It is prudent to recognize the risk of malignant hyperthermia during anesthesia in this disorder.
|Figure 1: (a-d) Typical phenotype (facial dysmorphism, low-set ears, pursed lips, microstomia, micrognathia and stiffness of facial expression) with the “herculean” or “body-builder like” appearance.|
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|Figure 2: (a-e) Facial and eyelid myotonia, opening eyelids with fingers, and myotonia in hands; (d,e) Skeletal features of Spondyloepiphyseal dysplasia- canoe (oar)-shaped ribs and bullet (oval) shaped lumbar vertebrae.|
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Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Informed patient consent was obtained for publication of the case details and [Figure 1] and [Figure 2].
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Conflicts of interest
There are no conflicts of interest.
| References|| |
Schwartz O, Jampel RS. Congenital blepharophimosis associated with a unique generalized myopathy. Arch Ophtalmol 1969;68:52-7.
Nicole S, Ben Hamida C, Beighton P, Bakouri S, Belal S, Romero N, et al.
Localization of the Schwartz-Jampel syndrome (SJS) locus to chromosome 1p34-p36.1 by homozygosity mapping. Hum Mol Genet 1995;4:1633-6.
[Figure 1], [Figure 2]