Our experience in PGD for single gene disorders

A total of 334 couples underwent 561 PGD cycles for 45 different indications (Table I).The mean maternal age was 31.8 ± 4.3 years, ranging from 21 to 44.

The single gene defects investigated included autosomal dominant (34 cycles; 22 couples), autosomal recessive (303 cycles; 191 couples) and X linked disorders (27 cycles; 15 couples). A total of 197 cycles, for 106 couples, were also performed for HLA matching.

Myotonic dystrophy was the most frequent autosomal dominant disease tested (n = 9). β-Thalassemia was the most frequent autosomal recessive disorder (n = 217), followed by cystic fibrosis (n = 40), and Spinal Muscular Atrophy (n = 15). Haemophilia A (n = 6) and Duchenne muscular dystrophy (n = 5%) were the most frequent X-linked disorders investigated.

A total of 4663 embryos were analysed. PCR amplification was successful in 6057 out of 6664 blastomeres (91.0%). Amplification failed for all the markers/loci tested in 607 blastomeres. The efficiency of amplification for the individual genetic conditions ranged from 80.0% to 100%, with an overall amplification rate of 92.4%. The ADO rates varied between the different loci/markers investigated, ranging from 0,0% to 12,9%, with an average ADO rate of 7.5%.

Overall, 4269 (91.6%) embryos were successfully genotyped in the 561 clinical cycles.

Following transfer of 758 embryos, 141 women had positive hCG levels (35.7% pregnancy rate per embryo transfer), 116 of which were confirmed with fetal sacs and heart beat. 25 pregnancies spontaneously miscarried within the first trimester and two ectopic pregnancies were terminated. 38 pregnancies are still ongoing, whereas the others 69 went to term without complications, resulting in the birth of healthy babies.

Table I

Disease	Gene	N. Cycles	N. Couples	N. of clinical pregnancies	N. of pregnancies still ongoing	N. of pregnancies delivered
Autosomal Dominant		34	22	8	3	5
Charcot Marie Tooth type 1A	PMP22	1	1	1	1	0
Congenital fibrosis of extraocular muscles	KIF21A	2	1	0	0	0
Hand-Foot-Uterus syndrome / Synopolydactlyly	HOXD13- HOXA13	2	1	0	0	1
Holt-Oram Syndrome	TBX5	1	1	1	0	1
Huntington	HD	3	3	2	1	1
Li-Fraumeni Syndrome	p53	2	1	0	0	0
Myotonic dystrophy	DMPK	9	5	0	0	0
Neurofibromatosis type 1	NF1	4	3	1	1	0
Retinoblastoma	RB1	4	2	0	0	0
Tuberossclerosis 1	TSC1	1	1	1	0	1
Spastic Paraplegia type3	SPG3A	1	1	1	0	1
Torsion dystonia, early onset	DYT1	3	1	1	0	2
Von Hippel-Lindau syndrome	VHL	1	1	0	0	0

Autosomal Recessive		240	156	55	19	36
3-Hydroxyisobutyryl-CoA hydrolase deficiency	HIBCH	1	1	0	0	0
Cystic Fibrosis	CFTR	40	30	9	1	7
Congenital adrenal hyperplasia	CYP21A2	3	3	1	1	0
Factor VII deficiency	F7	1	1	1	0	0
Familial Mediterranean Fever	MEVF	2	1	0	0	0
Gangliosidosis	GLB1	2	1
Homocystinuria	MTHFR	1	1	1	1	0
Hypomagnesemia	CLDN16	1	1	0	0	0
Limb-girdle muscular dystrophy type 2C	SGCG	1	1	0	0	0
Mevalonic aciduria	MVK	1	1	0	0	0
Mucopolysaccharidosis Type IIIA - Sanfilippo sindrome A	SGSH	5	1	1	1	0
Mucopolysaccharidosis type IIIB - Sanfilippo syndrome B	NAGLU	1	1	1	1	0
Mucopolysaccharidosis Type VI - Maroteaux-Lamy Syndrome	ARSB	2	1	1	0	1
Neuronal ceroid lipofuscinosis 1 - Batten's disease	PPT1	1	1	1	0	1
Niemann-Pick disease	SMPD1	1	1	1	1	0
Tay Sachs	HEXA	1	1	0	0	0
Thalassemia - β	HBB	217	127	31	9	21
Sickle cell anemia	HBB	7	4	2	1	1
Spinal Muscular Atrophy	SMN	15	13	5	3	3

X-linked		27	15	11	2	7
Adrenoleukodystrophy	ABCD1	3	2	1	1	0
Alpha-Thalassemia mental retardation syndrome	ATRX	1	1	0	0	0
Charcot Marie Tooth type X	CMTX	3	1	3	0	1
Chronic granulomatous disease	CYBB	1	1	1	0	2
Duchenne muscular dystrophy	DMD	5	2	1	0	1
Fragile - X	FRAXA	2	1	0	0	0
Glucose-6-phosphate dehydrogenase deficiency	G6PD	1	1	0	0	0
Haemophilia A	F8	6	3	3	1	1
Haemophilia B	F9	3	1	1	0	1
Lesch-Nyhan syndrome	HPRT	1	1	0	0	0
Wiskott-Aldrich Syndrome	WAS	1	1	1	0	1

Specific traits		197	106	42	14	20
SGD + HLA Matching	Gene + HLA	159	88	34	11	18
HLA Matching only	HLA	38	18	8	3	2
TOTAL	561	334		116	38	69

Table II

Disease
HOLT-ORAM syndrome	1	1	6	12	11	91,7	6	100,0
Charcot Marie Tooth type 1A (CMT1A)	1	1	7	14	13	92,9	7	100,0
congenital fibrosis of extraocular muscles	2	1	21	21	21	100,0	21	100,0
Myotonic dystrophy (DM)	9	5	41	63	56	88,9	38	92,7
Torsion dystonia, early onset (EOTD)	3	1	26	52	48	92,3	26	100,0
HAND-FOOT-UTERUS SYNDROME/SYNPOLYDACTYLY	2	1	18	11	10	90,9	15	83,3
Huntington	3	3	22	31	30	96,8	21	95,5
Li-Fraumeni (P53)	2	1	12	24	24	100,0	12	100,0
Neurofibromatosi type 1	4	3	19	33	28	84,8	14	73,7
Retinoblastoma	4	2	28	56	53	94,6	28	100,0
Tuberosclerosis	1	1	4	8	8	100,0	4	100,0
Spastic paraplegia type 3	1	1	12	22	21	95,5	11	91,7
von Hippel-Lindau sindrome	1	1	2	4	4	100,0	2	100,0
Total Auttosomal dominant	34	22	218	351	327	93.2	205	1237

β-Thalassemia	217	127	1889	2687	2421	90,1	1674	88,6
Cystic Fibrosis	40	30	243	371	336	90,6	227	93,4
Batten's disease	1	1	6	6	5	83,3	5	83,3
Congenital adrenal hyperplasia (CAH)	3	3	32	33	27	81,8	26	81,3
Factor VII deficiency	1	1	18	18	18	100,0	18	100,0
Familial Mediterranean Fever (FMF)	2	1	4	8	8	100,0	4	100,0
GANGLIOSIDOSIS	2	1	6	11	10	90,9	6	100,0
3-Hydroxyisobutyryl-CoA hydrolase def	1	1	10	10	10	100,0	10	100,0
hypomagnesemia	1	1	13	13	8	61,5	8	61,5
Homocystinuria	1	1	2	4	4	100,0	2	100,0
Mevalonic aciduria	1	1	6	6	5	83,3	5	83,3
Mucopolysaccharidosis Type IIIA - Sanfilippo sindrome A (MPS3A)	5	1	46	68	60	88,2	40	87,0
Mucopolysaccharidosis Type IIIB - Sanfilippo sindrome B (MPS3B)	1	1	4	8	8	100,0	4	100,0
Mucopolysaccharidosis Type VI (MPS VI) - Maroteaux-Lamy Syndrome	2	1	10	16	12	75,0	7	70,0
Limbe-gridle Muscular dystrophy	1	1	5	9	8	88,9	4	80,0
Niemann-Pick disease	1	1	0	15	14	93,3	14	0
Tay Sacs	1	1	10	20	20	100,0	10	100,0
Sickle cell	7	4	45	80	75	93,8	41	91,1
Spinal Muscular Atrophy (SMA)	15	13	98	149	127	85,2	86	87,8
Total Auttosomal recessive	303	191	2447	3532	3176	90.0	2191	0

Adrenoleukodystrophy	3	2	13	19	19	100,0	13	100,0
Lesch-Nyhan syndrome	1	1	2	4	4	100,0	2	100,0
Charcot Marie Tooth type X (CMTX)	3	1	29	35	33	94,3	27	93,1
Chronic granulomatous disease	1	1	15	15	15	100,0	15	100,0
Duchenne muscular dystrophy	5	2	24	48	42	87,5	24	100,0
Glucose-6-phosphate dehydrogenase deficiency	1	1	15	30	28	93,3	14	93,3
Fragile-X	2	1	18	18	14	77,8	14	77,8
Haemophilia A	6	3	25	46	41	89,1	24	96,0
Haemophilia B	3	1	20	40	36	90,0	20	100,0
Lesch-Nyhan (HPRT)	1	1	7	14	12	85,7	7	100,0
Wiskott-Aldrich Syndrome	1	1	13	20	18	90,0	9	69,2
Total X-linked	27	15	181	289	262	90.7	169	1029

SGD+HLA matching	159	88	1488	2077	1914	92,2	1402	94,2
HLA Matching only	38	18	329	415	378	91,1	302	91,8
Total	561	334	4663	6664	6057	91.0	4269	91,6

Table III

Disease	s
HOLT-ORAM syndrome	1	1	2	1	100,0	0	1	0	0	100,0	100,0	1
Charcot Marie Tooth type 1A (CMT1A)	1	1	1	1	100,0	0	1	0	1	100,0	100,0	0
congenital fibrosis of extraocular muscles	2	1	4	0	0,0	0	0	0	0	0,0	0,0	0
Myotonic dystrophy (DM)	9	5	10	1	16,7	1	0	0	0	0,0	0,0	0
Torsion dystonia, early onset (EOTD)	3	1	8	1	33,3	0	1	0	0	33,3	100,0	2
HAND-FOOT-UTERUS SYNDROME/SYNPOLYDACTYLY	2	1	0	0	0	0	0	0	0	0	0,0	0
Huntington	3	3	8	2	66,7	0	2	0	1	66,7	66,7	1
Li-Fraumeni (P53)	2	1	5	0	0,0	0	0	0	0	0,0	0,0	0
Neurofibromatosi type 1	4	3	3	2	66,7	1	1	0	1	33,3	33,3	0
Retinoblastoma	4	2	9	1	25,0	1	0	0	0	0,0	0,0	0
Tuberosclerosis	1	1	1	1	100,0	0	1	0	0	100,0	100,0	1
Spastic paraplegia type 3	1	1	1	1	100,0	0	1	0	0	100,0	100,0	1
von Hippel-Lindau sindrome	1	1	1	0	0,0	0	0	0	0	0,0	0,0	0
Total Auttosomal dominant	34	22	53	11	0	3	8	0	3	0	600	6

β-Thalassemia	217	127	265	40	30,5	9	31	12	9	23,7	24,4	21
Cystic Fibrosis	40	30	88	9	23,7	0	9	1	1	23,7	30,0	7
Batten's disease	1	1	1	1	100,0	0	1	0	0	100,0	100,0	1
Congenital adrenal hyperplasia (CAH)	3	3	7	1	33,3	0	1	0	1	33,3	33,3	0
Factor VII deficiency	1	1	3	1	100,0	0	1	0	0	100,0	100,0	2
Familial Mediterranean Fever (FMF)	2	1	3	1	100,0	1	0	0	0	0,0	0,0	0
GANGLIOSIDOSIS	2	1	3	0	0,0	0	0	0	0	0,0	0,0	0
3-Hydroxyisobutyryl-CoA hydrolase def	1	1	3	0	0,0	0	0	0	0	0,0	0,0	0
hypomagnesemia	1	1	2	0	0,0	0	0	0	0	0,0	0,0	0
Homocystinuria	1	1	1	1	100,0	0	1	0	1	100,0	100,0	0
Mevalonic aciduria	1	1	2	0	0,0	0	0	0	0	0,0	0,0	0
Mucopolysaccharidosis Type IIIA - Sanfilippo sindrome A (MPS3A)	5	1	15	3	60,0	2	1	0	1	20,0	100,0	0
Mucopolysaccharidosis Type IIIB - Sanfilippo sindrome B (MPS3B)	1	1	3	1	100,0	0	1	0	1	100,0	100,0	0
Mucopolysaccharidosis Type VI (MPS VI) - Maroteaux-Lamy Syndrome	2	1	4	1	50,0	0	1	0	0	50,0	100,0	1
Limbe-gridle Muscular dystrophy	1	1	3	0	0,0	0	0	0	0	0,0	0,0	0
Niemann-Pick disease	1	1	2	1	100,0	0	1	0	1	100,0	100,0	0
Tay Sacs	1	1	3	0	0,0	0	0	0	0	0,0	0,0	0
Sickle cell	7	4	14	3	42,9	1	2	0	1	28,6	50,0	1
Spinal Muscular Atrophy (SMA)	15	13	28	5	38,5	0	5	0	3	38,5	38,5	3
Total Auttosomal recessive	303	191	450	68	879	13	55	13	19	718	876	36

Adrenoleukodystrophy	3	2	2	1	50,0	0	1	0	1	50,0	50,0	0
Lesch-Nyhan syndrome	1	1	0	0	0	0	0	0	0	0	0,0	0
Charcot Marie Tooth type X (CMTX)	3	1	7	3	100,0	0	3	2	0	100,0	300,0	1
Chronic granulomatous disease	1	1	2	1	100,0	0	1	0	0	100,0	100,0	2
Duchenne muscular dystrophy	5	2	8	1	25,0	0	1	0	0	25,0	50,0	1
Glucose-6-phosphate dehydrogenase deficiency	1	1	3	0	0,0	0	0	0	0	0,0	0,0	0
Fragile-X	2	1	1	1	100,0	1	0	0	0	0,0	0,0	0
Haemophilia A	6	3	13	3	50,0	0	3	1	1	50,0	100,0	1
Haemophilia B	3	1	5	1	33,3	0	1	0	0	33,3	100,0	1
Lesch-Nyhan (HPRT)	1	1	2	0	0,0	0	0	0	0	0,0	0,0	0
Wiskott-Aldrich Syndrome	1	1	1	1	100,0	0	1	0	0	100,0	100,0	1
Total X-linked	27	15	44	12	0	1	11	3	2	0	800	7

SGD+HLA matching	159	88	165	41	39,0	7	34	8	11	32,4	38,6	18
HLA Matching only	38	18	46	9	33,3	1	8	3	3	29,6	44,4	2
Total	561	334	758	141	35,7	25	116	27	38	29,4	34,7	69