Table 2. [International Pachyonychia Congenita Research Registry (IPCRR) Data Summary (as of 10 May 2017)]. - GeneReviews®

Gene in Which Pathogenic Variants Were Confirmed	KRT6A	KRT6B	KRT6C	KRT16	KRT17	TOTAL
Number evaluated for finding ¹	304	71	22	247	130	774
Toenails thickened
10 toenails	286 (94%)	26 (37%)	0 (00%)	99 (40%)	100 (77%)	511 (66%)
7-9 toenails	9 (03%)	14 (20%)	0 (00%)	52 (21%)	11 (08%)	86 (11%)
4-6 toenails	2 (01%)	21 (30%)	3 (14%)	63 (26%)	7 (05%)	96 (12%)
1-3 toenails	4 (01%)	9 (13%)	10 (45%)	44 (18%)	8 (06%)	75 (10%)
Total w/toenails thickened	301 (99%)	70 (99%)	13 (59%)	238 (96%)	126 (97%)	748 (97%)
Age at onset	Birth - <1 yr	264 (88%)	10 (14%)	1 (08%)	45 (19%)	92 (73%)	412 (54%)
1-4 yrs	33 (11%)	19 (27%)	6 (46%)	78 (33%)	24 (19%)	160 (21%)
5-14 yrs	4 (01%)	34 (49%)	4 (31%)	74 (31%)	10 (08%)	126 (17%)
≥15 yrs	0 (00%)	7 (10%)	2 (15%)	43 (18%)	1 (01%)	53 (07%)
Fingernails thickened
10 fingernails	271 (89%)	4 (06%)	0 (00%)	73 (30%)	62 (48%)	410 (53%)
7-9 fingernails	10 (03%)	4 (06%)	0 (00%)	11 (04%)	13 (10%)	38 (05%)
4-6 fingernails	14 (05%)	17 (24%)	0 (00%)	30 (12%)	28 (22%)	89 (11%)
1-3 fingernails	6 (02%)	7 (10%)	0 (00%)	28 (11%)	9 (07%)	50 (06%)
Total w/fingernails thickened	301 (99%)	32 (45%)	0 (00%)	142 (57%)	112 (86%)	587 (76%)
Age at onset	Birth - <1 yr	267 (89%)	4 (13%)	0 (00%)	33 (23%)	85 (76%)	389 (66%)
1-4 yrs	30 (10%)	8 (25%)	0 (00%)	42 (30%)	19 (17%)	99 (17%)
5-14 yrs	3 (01%)	11 (34%)	0 (00%)	34 (24%)	6 (05%)	54 (09%)
≥15 yrs	1 (00%)	10 (31%)	0 (00%)	34 (24%)	3 (03%)	48 (08%)
Plantar keratoderma
Always (never completely goes away)	254 (84%)	67 (94%)	19 (86%)	240 (97%)	86 (66%)	666 (86%)
Sometimes (feet clear up completely at times)	7 (02%)	1 (01%)	0 (00%)	1 (00%)	14 (11%)	23 (03%)
Seldom (feet usually clear of symptoms)	5 (02%)	0 (00%)	0 (00%)	0 (00%)	4 (03%)	9 (01%)
Total w/plantar keratoderma	266 (88%)	68 (96%)	19 (86%)	241 (98%)	104 (80%)	698 (90%)
Age at onset	Birth - <1 yr	39 (15%)	2 (03%)	1 (05%)	23 (10%)	12 (12%)	77 (11%)
1-4 yrs	152 (57%)	23 (34%)	9 (47%)	130 (54%)	35 (34%)	349 (50%)
5-14 yrs	70 (26%)	42 (62%)	9 (47%)	82 (34%)	43 (41%)	246 (35%)
≥15 yrs	5 (02%)	1 (01%)	0 (00%)	8 (03%)	15 (14%)	29 (04%)
Plantar pain w/plantar keratoderma ²
Often require medication for pain	65 (24%)	12 (18%)	5 (26%)	74 (31%)	19 (18%)	175 (25%)
Very painful, but do not use medication	114 (43%)	32 (47%)	11 (58%)	111 (46%)	34 (33%)	302 (43%)
Somewhat painful	77 (29%)	24 (35%)	3 (16%)	50 (21%)	36 (35%)	190 (27%)
Total w/plantar keratoderma/pain	256 (96%)	68 (100%)	19 (100%)	235 (98%)	89 (86%)	667 (96%)
Palmar keratoderma
Always (never completely goes away)	86 (28%)	11 (15%)	2 (09%)	148 (60%)	21 (16%)	268 (35%)
Sometimes (hands clear up completely at times)	32 (11%)	7 (10%)	1 (05%)	15 (06%)	22 (17%)	77 (10%)
Seldom (hands usually clear of symptoms)	49 (16%)	13 (18%)	3 (14%)	22 (09%)	27 (21%)	114 (15%)
Total w/palmar keratoderma	167 (55%)	31 (44%)	6 (27%)	185 (75%)	70 (54%)	459 (59%)
Additional findings
Oral leukokeratosis	269 (88%)	18 (25%)	4 (18%)	88 (36%)	34 (26%)	413 (53%)
Cysts	188 (62%)	49 (69%)	4 (18%)	64 (26%)	121 (93%)	426 (55%)
Follicular hyperkeratosis	162 (53%)	30 (42%)	0 (00%)	30 (12%)	86 (66%)	308 (40%)
Natal or prenatal teeth	12 (04%)	0 (00%)	0 (00%)	0 (00%)	99 (76%)	111 (14%)

Gene in Which Pathogenic
Variants Were Confirmed

KRT6A

KRT6B

KRT6C

KRT16

KRT17

TOTAL

Number evaluated for finding ¹

304

247

130

774

Toenails thickened

10 toenails

286 (94%)

26 (37%)

0 (00%)

99 (40%)

100 (77%)

511 (66%)

7-9 toenails

9 (03%)

14 (20%)

0 (00%)

52 (21%)

11 (08%)

86 (11%)

4-6 toenails

2 (01%)

21 (30%)

3 (14%)

63 (26%)

7 (05%)

96 (12%)

1-3 toenails

4 (01%)

9 (13%)

10 (45%)

44 (18%)

8 (06%)

75 (10%)

Total w/toenails thickened

301 (99%)

70 (99%)

13 (59%)

238 (96%)

126 (97%)

748 (97%)

Age
at
onset

Birth - <1 yr

264 (88%)

10 (14%)

1 (08%)

45 (19%)

92 (73%)

412 (54%)

1-4 yrs

33 (11%)

19 (27%)

6 (46%)

78 (33%)

24 (19%)

160 (21%)

5-14 yrs

4 (01%)

34 (49%)

4 (31%)

74 (31%)

10 (08%)

126 (17%)

≥15 yrs

0 (00%)

7 (10%)

2 (15%)

43 (18%)

1 (01%)

53 (07%)

Fingernails thickened

10 fingernails

271 (89%)

4 (06%)

0 (00%)

73 (30%)

62 (48%)

410 (53%)

7-9 fingernails

10 (03%)

4 (06%)

0 (00%)

11 (04%)

13 (10%)

38 (05%)

4-6 fingernails

14 (05%)

17 (24%)

0 (00%)

30 (12%)

28 (22%)

89 (11%)

1-3 fingernails

6 (02%)

7 (10%)

0 (00%)

28 (11%)

9 (07%)

50 (06%)

Total w/fingernails thickened

301 (99%)

32 (45%)

0 (00%)

142 (57%)

112 (86%)

587 (76%)

Age
at
onset

Birth - <1 yr

267 (89%)

4 (13%)

0 (00%)

33 (23%)

85 (76%)

389 (66%)

1-4 yrs

30 (10%)

8 (25%)

0 (00%)

42 (30%)

19 (17%)

99 (17%)

5-14 yrs

3 (01%)

11 (34%)

0 (00%)

34 (24%)

6 (05%)

54 (09%)

≥15 yrs

1 (00%)

10 (31%)

0 (00%)

34 (24%)

3 (03%)

48 (08%)

Plantar keratoderma

Always (never completely goes away)

254 (84%)

67 (94%)

19 (86%)

240 (97%)

86 (66%)

666 (86%)

Sometimes (feet clear up completely at times)

7 (02%)

1 (01%)

0 (00%)

1 (00%)

14 (11%)

23 (03%)

Seldom (feet usually clear of symptoms)

5 (02%)

0 (00%)

4 (03%)

9 (01%)

Total w/plantar keratoderma

266 (88%)

68 (96%)

19 (86%)

241 (98%)

104 (80%)

698 (90%)

Age
at
onset

Birth - <1 yr

39 (15%)

2 (03%)

1 (05%)

23 (10%)

12 (12%)

77 (11%)

1-4 yrs

152 (57%)

23 (34%)

9 (47%)

130 (54%)

35 (34%)

349 (50%)

5-14 yrs

70 (26%)

42 (62%)

9 (47%)

82 (34%)

43 (41%)

246 (35%)

≥15 yrs

5 (02%)

1 (01%)

0 (00%)

8 (03%)

15 (14%)

29 (04%)

Plantar pain w/plantar keratoderma ²

Often require medication for pain

65 (24%)

12 (18%)

5 (26%)

74 (31%)

19 (18%)

175 (25%)

Very painful, but do not use medication

114 (43%)

32 (47%)

11 (58%)

111 (46%)

34 (33%)

302 (43%)

Somewhat painful

77 (29%)

24 (35%)

3 (16%)

50 (21%)

36 (35%)

190 (27%)

Total w/plantar keratoderma/pain

256 (96%)

68 (100%)

19 (100%)

235 (98%)

89 (86%)

667 (96%)

Palmar keratoderma

Always (never completely goes away)

86 (28%)

11 (15%)

2 (09%)

148 (60%)

21 (16%)

268 (35%)

Sometimes (hands clear up completely at times)

32 (11%)

7 (10%)

1 (05%)

15 (06%)

22 (17%)

77 (10%)

Seldom (hands usually clear of symptoms)

49 (16%)

13 (18%)

3 (14%)

22 (09%)

27 (21%)

114 (15%)

Total w/palmar keratoderma

167 (55%)

31 (44%)

6 (27%)

185 (75%)

70 (54%)

459 (59%)

Additional findings

Oral leukokeratosis

269 (88%)

18 (25%)

4 (18%)

88 (36%)

34 (26%)

413 (53%)

Cysts

188 (62%)

49 (69%)

4 (18%)

64 (26%)

121 (93%)

426 (55%)

Follicular hyperkeratosis

162 (53%)

30 (42%)

0 (00%)

30 (12%)

86 (66%)

308 (40%)

Natal or prenatal teeth

12 (04%)

0 (00%)

99 (76%)

111 (14%)

From: Pachyonychia Congenita

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Adam MP, Feldman J, Mirzaa GM, et al., editors.

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