We observed the pattern of muscle weakness in 28 patients from 13 families with 4q35-linked EcoRI/BlnI DNA fragment size 13-30 kb facioscapuloperoneal muscular dystrophy (FSPMD) Thirteen patients (8 men and 5 women) from these families were re-examined by V.K. after a period ranging from 27 to 49 years. In particular: a) after 27-29 years: 4 patients ( F5, IV-7, aged 52; F8, II-13, aged 88 and III-25, aged 55; F13a, III-1, aged 45); b) after 36-37 years: 5 patients (F2, III-7, aged 73, III- 10, aged 73 and VI-8, aged 42; F8, VI-17, aged 41; F13, III-8, aged 63); c) after 43 years: 1 patient (F20, IV-2, aged 61); d) after 48 years: 1 patient (F15, IV-3, aged 68); and e) after 49 years: 2 patients(F18, III-3, aged 67; F9a, IV-1, aged 74).
In the first examination the following phenotypes of muscle weakness were found: a) facio(scapular) [F(S)] (3 patients); b) (facio)scapular [(F)S] (1); c) facioscapular (FS) (1); d) (facio)scapuloperoneal [(F)SP] (5); e) (facio) scapuloperoneal-(femoral) [(F)SP(F)] (1); f) scapuloperoneal (SP) (1); g) facio-scapulo-peroneal-(humeral) [FSP(H)] (1) (see appendix for legenda of phenotypes).
On re-examination after 27-49 years, the following phenotypes were observed: a) facio-scapulo-peroneal- femoro (posterior thigh muscles)-gluteo (gluteus maximus) (FSPFG) (3 patients); b) facio-scapulo-peroneal- femoro (posterior thigh muscles)-gluteo (gluteus maximus)- (humeral; biceps brachii) [FSPFG(H)] (4 patients); c) facio-scapulo-peroneal-humero (biceps brachii) - femoral (posterior thigh muscles)-gluteal (gluteus maximus) (FSPHFG) (2 patients); d) (facio)scapuloperoneal [(F)SP)] (2 patients); e) facioscapuloperoneal (FSP) (1 patient) and f) facioscapuloperoneal-(femoral) [FSP(F)] (1 patient). Thus, in 9 patients the phenotype of muscle weakness was changed in FSPFG or FSPFG(H) phenotypes (7 patients) and in FSPHFG phenotype – where the biceps brachii muscles were severely affected following the involvement of tibialis anterior muscles (2 patients). However in all 9 patients, the interscapular and peroneal group muscles were more severely affected than posterior group of thigh and gluteus maximus muscles. Three patients (F2, III-10, aged 73 and VI-8, aged 42; F8, III- 25, aged 55) on re-examination after 37, 36 and 27 years respectively, remain in pure facioscapuloperoneal phenotype while in 1 patient (F8, VI-17) - after 36 years - the FSP phenotype predominated but with a slight involvement of posterior thigh muscles.
In 2 patients from F2 showing clinical pure FSP phenotype, a severe involvement of some posterior thigh muscles and rectus femoris was found on MRI of lower limbs. Thus, in all reported patients, the disease began with initial involvement of the face (in minimal/slight degree) and shoulder girdle muscles and sometime later with the involvement of the peroneal group (anterior tibial) muscles. However, the dystrophic process gradually extended to the thigh muscles (posterior group, namely; the quadriceps were preserved in 13/28 patients), pelvic girdle muscles (gluteus maximus, namely; the gluteus medius were preserved in 13/28 patients) but not always on upper arm muscles (biceps brachii, namely; slightly weakened on the one side in 4/13 patients; in two patients these muscles were severe affected).
The present clinical and MRI data, as well as our earlier investigations (1969-2009), allow us to suggest that the facioscapuloperoneal muscular dystrophy (FSPMD) is probably an independent form with "hard" static and dynamic pattern of muscle involvement and a mild course of the disease (1-3). All reported patients, including those examined at the age of 68, 73, 73 and 74 years, could walk independently while all but 2 (F13, III-8, aged 63 and F8, II-13, aged 88, who could walk with aid of a stick on short distances only) were able to climb the stairs with the aid of a railing. However, in first patient the FSPMD associated with aortic aneurism and in second one - with diabetic polyneuropathy. On re-examination after 3-20 years, 8 symptomatic patients the final phenotype was unchanged FSPFGH (2 men), FSPFG(H) (1 man), FSPHFG (3 men), FSPFG (1 man) and (F)SP(FG) (1 man).
In conclusion, in our opinion, the term "facio-scapulo- limb muscular dystrophy, type 2 (FSLD2), descending with a "jump" with initial FSP phenotype" would be more correct. The FSP or (F)SP phenotype constitutes merely a stage in the development of FSLD2. We suppose that classical AD FSPMD (or FSLD2, a descending with a "jump" with initial FSP phenotype, Erb, Landouzy and Dejerine type) is an allelic form of the classical AD FSHD (which we called as a facioscapulolimb muscular dystrophy, type 1 (FSLD1), a gradually descending with initial FSH phenotype, Duchenne de Boulogne type), both connected with the same 4q35 chromosomal deletion.