Table 1 Patient characteristics

Patient age at the time of the survey

 Age of all patients

138

18 years (6–38); 22.7 ± 18

  Number of paediatric patients (≤ 18 years)

69

  Age of patients identified by newborn screening

29

4 years (2–22); 11.5 ± 13.2

  Age of clinically ascertained patients

76

21 years (10–38); 24.8 ± 17.3

N

%

Participants

143

 Male

60

42

 Female

81

56.6

 No information provided

2

1.4

Informants

 Caregivers

82

57.3

 Adult patients (> 18 years)

55

38.5

 Adolescent patients (< 18 years)

2

1.4

 Health professionals

3

2.1

 No information provided

1

0.7

Countries of origin

141

 USA

46

32.6

 Czech Republic

20

14.2

 United Kingdom

19

13.5

 Australia

17

12.1

 Ireland

8

5.7

 Germany

6

4.3

 Other European countries

9

6.5

 South America

4

2.8

 Asia

4

2.8

 Canada

4

2.8

 Africa

2

1.4

 New Zealand

2

1.4

Diagnosis

142

   Cystathionine beta-synthase (CBS) deficiency

110

77.5

  Pyridoxine nonresponsive

62

   Diagnosed by newborn screening

21

  Partially pyridoxine responsive

8

   Diagnosed by newborn screening

1

  Pyridoxine responsive

28

   Diagnosed by newborn screening

–

  Unsure of responsiveness

12

   Diagnosed by newborn screening

2

 Remethylation defects (RMD)

24

16.9

  cblC

10

   Diagnosed by newborn screening

4

  MTHFR deficiency

7

   Diagnosed by newborn screening

–

  cblE

3

   Diagnosed by newborn screening

–

  cblG

3

   Diagnosed by newborn screening

–

cblF

1-

Diagnosed by newborn screening

–

 Unsure of diagnosis

8

5.6

  Diagnosed by newborn screening

1