Analysis of SMN protein in umbilical cord blood and postnatal peripheral blood of neonates with SMA: a rationale for prompt treatment initiation to prevent SMA development

Table 2 Details of analysis data in five patients and their mothers

	SMN2 2 copies			SMN2 3 copies
(%SMN spot⁺ cells)	Case 1	Case 2	Case 3	Case 4	Case 5
Patients
Cord blood	0.1%	0.6%	13.1%	3.6%	24.0%
Deviation from SMA median (σ₁, σ₂)	− 0.7 σ₁	− 0.6 σ₁	+ 1.6 σ₁	− 0.6 σ₂	+ 2.0 σ₂
Peripheral blood ^a	0.9%*	0.4%*	3.0%*	2.5%	15.2%
Deviation from SMA median (σ₁, σ₂)	− 0.6 σ₁	− 0.7 σ₁	− 0.2 σ₁	− 0.8 σ₂	+ 0.8 σ₂
Blood sampling (age in days)	43d	29d	59d	7d	7d
Mothers
Peripheral blood	1.4%	2.5%	3.4%	2.7%	25.2%
Deviation from Carrier median (σ₃)	− 0.4 σ₃	− 0.3 σ₃	− 0.2 σ₃	− 0.3 σ₃	+ 2.4 σ₃

^aThe data of patients’ peripheral blood were obtained from the second postnatal blood drawing
^*Blood sampling day of Case1 (43d), Case 2 (29d), and Case 3 (59d) were after initiation of disease-modifying therapy (DMT). Details are described in Table 1 and below,
Case 1 received nusinersen at 3-day-old and onasemnogene abeparvovec at 11 days of age
Case 2 received nusinersen at 3-day-old and onasemnogene abeparvovec at 15 days of age
Case 3 received onasemnogene abeparvovec at 17 days of age
Numerical details are shown in the Additional file 3C, Median ± SD (σ) are as below
σ₁: 2 SMN2 copies group; 4.3% ± 5.7, σ₂: 3 SMN2 copies group; 8.6% ± 7.8, σ₃: Carrier group; 5.1% ± 8.5

ISSN: 1750-1172