Table 7

Urine excretion of cystine and dibasic amino acids in heterozygotes carrying the type B mutations (SLC7A9) associated with phenotype I

	Phenotype	n	Urine amino acid concentrations (μmol/g creatinine)
	Phenotype	n	Cystine	Lysine	Arginine	Ornithine	Sum
Values are mean (SEM) μmol/g creatinine or individual values.
R333W is a common mutation with phenotype non-I in all the heterozygotes studied. Urine excretion of amino acids for heterozygotes with one mutated SLC7A9 allele (B+) with phenotype non-I is also shown. Urine amino acid levels in controls are shown in table 6.
*Individual or mean values greater than 95th centile in controls (see table 6).
†A182T is not associated with mutation A354T in these alleles.
‡c.614dupA is the present nomenclature for mutation c.800–801insA.
NA, not analysed; ND, not detectable.
Common mutations
A182T/+†	I	6	82 (16)	151 (52)	31 (7)	21 (6)	285 (57)
	Non-I	5	373 (135)*	1865 (1022)*	151 (60)*	138 (50)*	2527 (1090)*
T123M/+	I	2	29, 229*	271, 140	8, 25	19, 10	327, 404
	Non-I	2	NA	2596, 734	42, 17	176*, 53	NA
V170M/+	I	4	112 (16)*	254 (54)	6 (2)	18 (5)	391 (64)
	Non-I	12	441 (87)*	1471 (391)*	46 (14)	129 (28)*	2087 (475)*
c.614dupA/+‡	I	1	260*	122	19	25	426
	Non-I	18	607 (95)*	2249 (260)*	90 (14)*	220 (31)*	3165 (342)*
G105R/+	I	1	26	456	35	13	530
	Non-I	31	524 (75)*	1685 (181)*	69 (13)*	184 (32)*	2461 (249)*
R333W/+	Non-I	19	634 (139)*	2371 (330)*	137 (74)*	163 (28)*	3304 (482)*

Uncommon mutations
G63R/+	I	2	60, 59	330, 322	11, 14	41, 38	442, 433
	Non-I	1	202*	504*	25	19	750*
A126T/+	I	1	140*	455	ND	8	603
	Non-I	2	308,338	1144,1373	ND, 102*	0, 237*	1452,2050
G195R/+	I	1	116*	428	ND	19	563
	Non-I	1	439*	1948*	63*	247*	2697*
Y232C/+	I	1	108	125	11	42	286
W69X/+	I	1	51	249	55*	22	377
Heterozygotes B+	Non-I	127	534 (37)	1930 (113)	76 (13)	198 (20)	2758 (154)
[5th, 95th centile]			[138, 1348]	[498, 4492]	[0, 337]	[21, 522]	[807, 6081]