Case#: Patient 1 is a 24-year-old Japanese man. His birth weight was 2300 g (~5 lbs) and he had graduated from a vocational school. Physical examination demonstrated a height of 156.6 cm (mean height of Japanese male at age 24 is 170.9 ± 6.0 (SD) cm, body weight of 45.8 kg (mean body weight of Japanese male at age 24 is 62.6 ± 9.8 (SD) kg according to the National Health and Nutrition Survey in Japan, 2006). He demonstrated overall intelligence quotient (IQ) of 101, verbal IQ of 93 and performance IQ of 112.

DiseaseAssertion: MPS1-S

FamilyInfo: He was born from nonconsanguineous, young and healthy parents. He had a healthy elder brother and an affected twin brother (Patient 2).

CasePresentingHPOs: Inguinal hernia (treated by surgical repair in childhood and again at age 20), systolic ejection heart murmur, umbilical hernia, scissor gait, Babinski sign, mild aortic valve stenosis, severe cervical cord compression (HP:0000023, HP:0031664, HP:0001537, HP:0012407, HP:0003487, HP:0001650, HP:0002341)

CaseHPOFreeText: Admitted to the hospital due to a 6-month history of progressive gait disturbance. Mental and motor development were normal. Past medical histories included Kawasaki disease at age 6 months. Deep tendon reflexes were mildly exaggerated in the upper extremities, and markedly exaggerated in the lower extremities with bilateral Babinski signs. Radiography of the chest demonstrated mild thoracic deformity and that of cervical spine demonstrated hypoplasia of vertebral body and spinous process. Brain MRI demonstrated enlarged perivascular space and small hyperintense lesions on fluid attenuated inversion recovery image. Cerebrospinal fluid (CSF) examinations demonstrated an elevated protein level (440 mg/dL; normal range 10–40 mg/dL), which would be resulted from CSF circulatory disturbance caused by severe spinal canal stenosis, without pleocytosis.

CaseNotHPOs: N/A

CaseNotHPOFreeText: N/A

CaseEnzymeAssay: N/A

CaseUrineGAGs: Urine chemistry examination demonstrated increased excretion of uronic acid (63.1 mg/g creatinine; normal range 8.3–12.3 mg/g creatinine).

CaseERT: N/A

CaseBMT: N/A

Variant1: c.164dup (p.Leu56AlafsTer7) (c.252insC - in paper but nomenclature is not current)

Variant1ClinVarID: 855487

Variant1CAID: CA355945969

Variant2: c.1121C>A (p.Thr374Asn) (c.1209C>A - in paper but nomenclature is not current)

Variant2ClinVarID: 4078984

Variant2CAID: CA355963378

AdditionalVariants: N/A

ParentalGenotype: N/A

PreviouslyPublished N/A