Schwartz-Jampel Syndrome Clinical Presentation

Updated: Jan 06, 2022
  • Author: Eli S Neiman, DO, FACN; Chief Editor: Nicholas Lorenzo, MD, CPE, MHCM, FAAPL  more...
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The parents of patients with Schwartz-Jampel syndrome (SJS) usually note dysmorphic features, muscle stiffness, and muscle weakness, frequently soon after birth or within the first year of life. They may report that their child's muscles are stiff and hypertrophic.

The stiffness is usually evident when the parents flex the child's limbs. The weakness takes the form of delay in achieving motor milestones. For example, walking frequently is delayed. Nevertheless, in most cases, the children do learn to walk and become entirely self-sufficient.

When they are older, patients notice the muscle stiffness, which is usually most severe in the thighs. Patients also report limitations of joint flexion in various joints, particularly the knees.

Signs of SJS also include the following:

  • Narrow palpebral fissures with normal eyelid development

  • Blepharospasm

  • Hypertrichosis of the eyelids - Ie, excessive hair, multiple rows of hair

  • Micrognathia

  • Unusual, flattened facies with a puckered facial appearance

  • Low set ears

  • High arched palate

  • Crossbite

  • Impacted teeth

  • Dentigerous cysts

  • Small muscle mass

Skeletal and joint deformities include the following:

  • Short neck

  • Pectus carinatum - Convex chest; ie, chest is bowed out

  • Kyphosis - Convex angulation of the spine, giving a humpback appearance

  • Abnormal curvature of the vertebrae (scoliosis, kyphosis, lordosis)

  • Clubfoot and/or flat feet

  • Coxa valga - Hip deformity involving an increased neck-shaft angle of the femur

  • Irregularity of the capital femoral epiphyses

  • Both muscle hypertrophy and atrophy

  • Chrondrodysplasia

  • Osteoporosis 

According to one report, the incidence of intellectual disability in patients with SJS is high (25%). However, most patients are of normal intelligence, and high intelligence is not incompatible with this condition. Poor speech articulation and drooling is common so affected individuals can be misdiagnosed as having intellectual disability.


Physical Examination

The dysmorphic features of SJS are usually evident on physical examination. Most patients are short with narrow palpebral fissures (blepharophimosis), flattened facies, and micrognathia. Some patients show blepharospasm in addition to the blepharophimosis. The muscles are stiff and they can be either hypertrophic or reduced in mass.

Bony abnormalities include the following:

  • Joint deformities and limitations of joint motion

  • Coxa valga

  • Irregularity of the capital femoral epiphyses

  • Kyphosis

  • Short neck

  • Pectus carinatum