Table 2.

Mutational analysis, clinical data and prenatal diagnosis of combined MMA and HC families

No.	Proband	Mutation Maternal	Mutation Paternal	Onset age	Clinical data			Follow-up	Fetus Genotype
					HC (μM)	MMA (μM)	Ocular abnormalit-ies
								(age and clinical details)
1*#	/	220delK	W203X	1 months	43	20.8	NA.	Dead of severe malnutrition at 6 months old	W203X, 220delK
2	R132X	W203X	R132X	6 months	99	187.3	Normal^	1.5y,developmental delay HC decreased to 60 μM
	W203X
3	G155R	G155R	c.567dupT	1 month	NA	75.1	nystagmus	MMA decreased to 24.6 μM
	c.567dupT
4#	/	W203X	220delK	3 weeks	NA.			Dead at 1 month old
5#	/	R73X	220delK	2 months	NA.			Dead at 8 month old
6*	R206W	R206W	W203X	40 days	158	45.1	nystagmus	3y,developmental delay,	R206W,
	W203X							HC, MMAare normal	——
7	W203X	W203X	220delK	10 days	131	958.9	nystagmus	developmental delay, malnutrition
	220delK
8*	W203X	W203X	W203X	2 weeks	174	215.2	Normal^	15 months, taking medicine promptly and properly for a period of time, the patient has being in good recovery	——,
	W203X								——
9#	/	220delK	W203X	NA.	NA.			Dead at 4 months old
10	W203X	W203X	W203X	3 months	108	29.4	Visual inattention nystagmus	6 months, Can’t raise his head, developmental delay
	W203X

Note: *indicates prenatal diagnosis families; # indicates the proband in the family was dead; / indicates that the genotype of the dead proband was not available; ——indicates no mutation was detected; ^ indicates the proband’s parents said it’s normal without test

HC:value of serum homocysteine (reference value:5-15 μM)

MMA:value of urine methylmalonic acid (reference value:0.2-3.6 μM)

NA.:not avaliable,bacause the patient is from other hospital or can’t get through telephone