Table 3.

Characteristics of eight study participants with FSHD somatic mosaicism. N/A = not applicable.

Study ID	Recruitment Detail	Age at examination	Symptomatic/ Asymptomatic/ Nonpenetrant carrier	Clinical Features	Size (U) and fraction (%) mosaic FSHD1 and parental alleles	MRC Sum Score	Clinical Severity Score (CSS)(0–5)	Age corrected CSS	FSHD Clinical Score
IC_AIM_00701	Father of non-mosaic IC_AIM_00551	60	Nonpenetrant	Not applicable (N/A)	[2U(40%);20U(60%)]	70	N/A	N/A	N/A
IC_AIM_00224	Mother of non-mosaic IC_AIM_00222	45	Asymptomatic	Mild scapular winging	[5U(60%); 31U(40%)]	70	1	44	1
IC_AIM_00961	Father of non-mosaic IC_AIM_00904	58	Asymptomatic	Mild Facial weakness	[3U(50%);19U(50%)]	70	0.5	17	1
IC_AIM_00413	Proband	30	Symptomatic (age of onset = 20 yrs)	Proximal UL weakness (asymmetric) Proximal LL weakness (asymmetric) Bilateral foot drop Bifacial weakness Popeye arm	[4U(75%); 26U(25%)]	43	4	267	13
IC_AIM_00715	Mother of non-mosaic IC_AIM_00123	35	Symptomatic (age of onset = 20 yrs)	Bifacial weakness Proximal UL weakness Scapular winging Lumbar hyperlordosis Beevor Shoulder Pain	[4U(60%); 37U(40%)]	61	3	174	6
IC_AIM_01083	Proband	17	Symptomatic (age of onset = 12 yrs)	Weakness of facial musculature Proximal muscle weakness in upper limbs Scapular winging Distal lower limb muscle weakness Proximal muscle weakness in lower limbs Hyperlordosis Elbow flexion contracture Shoulder pain Beevor sign	[2U(10%);19U(90%)]	56	3	353	8
IC_AIM_01215	Father of non-mosaic IC_AIM_01179	55	Nonpenetrant	N/A	[5U(30%);16U(70%)]	70	N/A	N/A	N/A
IC_AIM_01403	Mother of non-mosaic IC_AIM_01401	40	Asymtomatic	Beevor sign Bifacial weakness Scapular winging	[4U(95%);19U(5%)]	70	1	50	3