The Association Between Interleukin 1 Beta Promoter Polymorphisms And Keratoconus Incidence And Severity In An Egyptian Population

Figures & data

Table 1 Demographic And Clinical Criteria Of Keratoconus Cases And Healthy Controls

	Cases (n = 95)	Control (n = 126)	Test Of Significance	p
Age	28(18–38)	30(18–38)	U=5499.5	0.300
Sex
Male	50(52.6%)	60(47.6%)	χ^2=0.544	0.461
Female	45(47.4%)	66(52.4%)
Keratoconus Family History
Negative	81(85.3%)	–	–	–
Positive	14(14.7%)
Kf (D)	46(38–93)	43(39.1–47.9)	U=1857.0*	<0.001*
Ks (D)	49.7(40.1–98.)	44.2(41–48.8)	U=1063.5*	<0.001*
Kavg (D)	47.5(39.7–95.5)	43.7(40.4–48.2)	U=1219.0*	<0.001*
Pachymetry Thinnest µ	450(223–563)	513.5(441–639)	U=788.5*	<0.001*
Spherical Equivalent (D)	−5.1(−24 – 3)	−4(−12 – 6)	U=4432.5*	0.025*
Corneal Scar
Negative	90(94.7%)	–	–	–
Positive	5(5.3%)
Krumeich Classification
1	4(4.2%)	–	–	–
2	57(60.0%)
3	18(18.9%)
4	16(16.8%)

Notes: Qualitative data were described using number and percent, while abnormally distributed data were expressed in median (Min–Max). *Statistically significant at p ≤ 0.05. χ², p: χ² and p values for Chi-square test for comparing between the two groups. U, p: U and p values for Mann–Whitney test for comparing between the two groups.

Abbreviations: Kf, flattest corneal meridian; Ks, steepest corneal meridian; Kavg, average corneal curvature; D, diopter; µ, micron.

Table 2 Allelic And Genotypic Frequencies Of The Studied Single Nucleotide Polymorphisms (SNPs) In Keratoconus Cases And The Control Population, Showing Increased Keratoconus Risk Associated With T And G Alleles And TT And GG Genotypes

	Cases (n = 95)	Control (n = 126)	χ^2	p	OR	95% CI
						LL	UL
rs1143627	HW(χ^2=0.382, p=0.537)	HW(χ^2=0.652, p=0.419)
CC	9 (9.5%)	36 (28.6%)	20.888*	<0.001*	0.252	0.088	0.721
CT	34 (35.7%)	68 (53.9%)			0.471	0.230	0.966
TT	52 (54.8%)	22 (17.5%)			5.631	2.530	12.533
Allele
C	52 (27.3%)	139 (55.2%)	20.329*	<0.001*	0.302	0.178	0.513
T	138 (72.7%)	113 (44.8%)			3.313	1.950	5.63
rs16944	HW(χ^2=0.250, p=0.617)	HW(χ^2=2.694, p=0.101)
AA	7 (7.4%)	40 (31.7%)	35.326*	<0.001*	0.163	0.053	0.505
AG	33 (34.7%)	71 (56.4%)			0.402	0.196	0.827
GG	55 (57.9%)	15 (11.9%)			11.478	4.627	28.475
Allele
A	46 (24.2%)	154 (61.1%)	33.485*	<0.001*	0.210	0.122	0.362
G	144 (75.8%)	98 (38.9%)			4.770	2.765	8.23

Notes: *Statistically significant at p ≤ 0.05. χ², p: χ² and p values for Chi-square test for comparing between the two groups. If P < 0.05 – not consistent with HWE. Not accurate if <5 individuals in any genotype group.

Abbreviations: OR, odds ratio; CI, confidence interval; LL, lower limit; UL, upper Limit; HW, Hardy–Weinberg.

Table 3 Clinical Association Of Allele Frequencies Of The Studied SNPs In Keratoconus Cases, Showing Increased Curvature Of The Flattest Corneal Meridian Associated With The G Allele

	rs1143627		Test Of Significance	p	rs16944		Test Of Significance	p
	C (n = 52)	T (n = 138)			A (n = 46)	G (n = 144)
Age	28(18–38)	28(18–38)	U=3834.0	0.705	30(18–38)	28(18–38)	U=4017.5	0.236
Sex
Male	32 (61.5%)	67 (48.5%)	χ^2=2.768	0.096	25 (54.3%)	74 (51.4%)	χ^2=0.136	0.712
Female	20 (38.5%)	71 (51.5%)			21 (45.7%)	70 (48.6%)
KC Family History
Negative	47 (90.4%)	114 (82.6%)	χ^2=1.875	0.171	41 (89.1%)	117 (81.2%)	χ^2=2.107	0.147
Positive	5 (9.6%)	24 (17.4%)			5 (10.9%)	27 (18.8%)
Kf	45.8(38.9–72.8)	46.2(38.8–93)	U=3592.0	0.290	45.7(38.9–72.8)	46.2(38.8–93)	U=3692.5*	0.041*
Ks	49.6(43.4–77)	50.1(40.1–98.1)	U=3673.0	0.406	49.4(40.1–77)	50.7(43.4–98.1)	U=3858.5	0.109
Kavg	47.2(42.9–74.9)	47.8(39.7–95.5)	U=3632.0	0.344	47(39.7–74.9)	48.3(42.9–95.5)	U= 3820.5	0.088
Pachymetry Thinnest	454(250–517)	446(223–563)	U=3594.0	0.293	454(250–563)	446(223–517)	U= 3765.5	0.064
Spherical Equivalent	−5(−24 – 3)	−5.3(−24 – 3)	U=3192.5	0.649	−5.3(−24 – 2.8)	−4.9(−24–3)	U=3477.0	0.513
Corneal Scar
Negative	49 (94.3%)	130 (94.2%)	χ^2=0.033	1.000	44 (95.6%)	134 (93.1%)	χ^2=0.927	0.516
Positive	3 (5.7%)	8 (5.8%)			2 (4.4%)	10 (6.9%)

Notes: Qualitative data were described using number and percent, while abnormally distributed data were expressed in median (Min–Max). *Statistically significant at p ≤ 0.05. χ², p: χ² and p values for Chi-square test for comparing between the two groups. U, p: U and p values for Mann–Whitney test for comparing between the two groups.

Table 4 Clinical Association Of Genotype Frequencies Of The Studied SNPs In Keratoconus Cases, Showing Increased Corneal Curvature Associated With GG Genotype

	rs1143627			Test Of Significance	p	rs16944			Test Of Significance	p
	CC (n = 9)	CT (n = 34)	TT (n = 52)			AA (n = 7)	AG (n = 33)	GG (n = 55)
Age	27 (18–38)	28.5(20–38)	28(18–38)	H= 0.665	0.717	30(18–38)	31(20–38)	25(18–38)	H= 3.593	0.166
Kf	46.7(43.6–72.8)	45.5(38.9–61.6)	46.4(38.8–93)	H= 4.981	0.083	46.1(39.1–72.8)	45.2(38.9–61.6)	47.8(38.8–93)	H=9.254*	0.010*
Ks	51.8(44.5–77)	48.7(43.4–65.6)	51.2(40.1–98.1)	H= 4.879	0.087	49.6(40.1–77)	48.8(43.4–65.6)	53(45.5–98.1)	H=6.176*	0.046*
Kavg	48.9(44.1–74.9)	46.7(42.9–63.6)	48.8(39.7–95.5)	H= 5.547	0.062	47.7(39.7–74.9)	46.7(42.9–63.6)	50.6(44.3–95.5)	H=7.539*	0.023*
Pachymetry thinnest	454(250–482)	453.5(296–517)	444.5(223–563)	H= 1.736	0.420	450(250–563)	455(296–517)	442(223–512)	H=3.178	0.204
Spherical equivalent	−5.6(−7.5 – −2.8)	−5(−24–3)	−5.3(−18.8–1)	H= 0.389	0.823	−5.3(−18.8 – −0.8)	−5.3(−24 – 3)	−4.8(−17.5–1)	H=0.206	0.902

Notes: Qualitative data were described using number and percent, while abnormally distributed data were expressed in median (Min–Max). *: Statistically significant at p ≤ 0.05. χ², p: χ² and p values for Chi-square test for comparing between the two groups. H, p: H and p values for Kruskal–Wallis test.

Figure 1 Scheimpflug tomography of a keratoconus patient (Krumeich class 4), with GG rs16944 genotype.