Satoyoshi Syndrome

Description

Satoyoshi syndrome is a rare disorder characterized by progressive, painful, intermittent muscle spasms, diarrhea or unusual malabsorption, endocrinopathy with amenorrhea, and secondary skeletal abnormalities. The disorder is also called komuragaeri disease by the Japanese; in Japanese 'komura' means calf and 'gaeri' means 'turnover' or spasm. All cases have apparently been sporadic, even when occurring in large families (Ehlayel and Lacassie, 1995).

Clinical Features

Satoyoshi and Yamada (1967) first reported this disorder in 2 patients with recurrent muscle spasms.

Ehlayel and Lacassie (1995) reported a 19.5-year-old woman who presented with primary amenorrhea, alopecia, bony deformities, and short stature. Alopecia began at the age of 9.5 years, and recurrent painful cramps in the calves and thighs, induced by physical exercise or emotional distress, began at the age of 10 years. Spasms in the masticatory muscles interfered with eating. Muscle relaxants had no favorable effect. Because deformities in both knees caused difficulty in walking, 5 operations were performed between the ages of 14 and 19 years. Muscle spasms improved after 4 weeks and totally disappeared by the eighth week of treatment with prednisone. Hair growth was noted after 6 weeks of treatment, and 2 episodes of light vaginal bleeding were observed during the first 3 months of treatment. Extensive immunologic evaluation of the patient reported by Ehlayel and Lacassie (1995), however, showed no detectable autoimmune abnormality. Their patient also had no evidence of malabsorption on extensive gastrointestinal evaluation.

Cecchin et al. (2003) described a 12-year-old Caucasian girl who presented with manifestations characteristic of Satoyoshi syndrome, including short stature, alopecia, and muscle cramps, with onset at age 7 years. After 2 months of treatment with prednisone every other day and amytriptiline daily, alopecia had significantly improved and muscle cramps had almost disappeared, so that glucocorticoid treatment was tapered. Follow-up 9 months later showed a normal-looking and asymptomatic girl.

Venegas-Vega et al. (2009) reported a 26-year-old Mexican woman, born of consanguineous parents, with short stature, alopecia, muscle spasms, and amenorrhea. Growth and development were normal until 6 years of age, when alopecia began, followed 1 year later by painful muscle cramps in the legs and feet. She had menarche at age 12 with oligomenorrhea followed by amenorrhea at age 16. Physical examination at age 26 showed alopecia, beaked nose with columella below alae nasi, narrow maxilla, prognathism, mild atrophic subcutaneous tissues, underdeveloped mammary glands, and no axillary or pubic hair. The muscles of the upper and lower limbs were hypertrophic, with normal strength. Skeletal anomalies included mild genu valgus, lumbar scoliosis, short hands and feet with short fingers and toes, clinodactyly, broad thumbs, mild hallux valgus, and pes planus. Laboratory studies showed mildly increased serum creatine kinase and uric acid, highly elevated serum IgE, and presence of antinuclear antibody with speckled pattern. Radiographic studies showed brachymetacarpism with short phalanges and short metatarsals. Pelvic ultrasound showed hypoplastic uterus and ovaries. Treatment with tetrazepam and carbamazepine resulted in decreased muscle spasms. Venegas-Vega et al. (2009) noted the unusual skeletal findings in this patient, but suggested that they may be unrelated to the disorder.

Diagnosis

In a review, Ehlayel and Lacassie (1995) presented the cardinal clinical features of Satoyoshi syndrome. Progressive painful intermittent muscle spasms usually start between 6 to 15 years of age (average age, 10.6 years). Alopecia universalis also appears around age 10. Approximately half of the patients show malabsorption, preferentially of carbohydrates. Skeletal abnormalities mimic a metaphyseal chondrodysplasia. Slipping of multiple epiphyses, cystic lesions, acroosteolysis and osteolysis, bone fragmentation at tendinous insertions, fatigue fractures, and early osteoarthrosis have been reported. The skeletal abnormalities may be secondary to muscle spasms. The main endocrine disorder is primary amenorrhea.

Differential Diagnosis

Ehlayel and Lacassie (1995) provided a useful differential diagnosis of muscle spasms, progressive short stature, and alopecia. Some of the features resemble cartilage-hair hypoplasia (CHH; 250250).

Pathogenesis

The pathogenesis of Satoyoshi syndrome has been thought to involve an autoimmune mechanism. Support for this hypothesis includes favorable response of muscular spasms, amenorrhea, and alopecia to glucocorticoids; the association of some cases with myasthenia gravis, nephritis, and idiopathic thrombocytopenia; and the deposition of immune complexes at the motor endplate of biceps muscle; as well as positive antinuclear antibodies (ANA) of speckled pattern (Ehlayel and Lacassie, 1995).

Drost et al. (2004) presented a 6-year-old Turkish girl with Satoyoshi syndrome. Laboratory investigation showed the presence of serum ANA and antibodies to glutamate decarboxylase (GAD; 138275), supporting an autoimmune etiology. The patient responded to prednisone treatment. The authors noted that 65% of patients with stiff man syndrome (184850) may have GAD antibodies.