Orofacial Muscle Weakening in Facioscapulohumeral Muscular Dystrophy (FSHD) Patients

Background: Facioscapulohumeral muscular dystrophy is the third most commonly found type of muscular dystrophy. The aim of this study was to correlate the D4Z4 repeat array fragment size to the orofacial muscle weakening exhibited in a group of patients with a genetically supported diagnosis of FSHD. Methods: Molecular genetic analysis was performed for 52 patients (27 female and 25 male) from a group that consisted of 36 patients with autosomal dominant pedigrees and 16 patients with either sporadic or unknown family status. The patients were tested with the southern blotting technique, using EcoRI/Avrll double digestion, and fragments were detected by a p13E-11 telomeric probe. Spearman’s correlation was used to compare the fragment size with the degree of muscle weakening found in the forehead, periocular and perioral muscles. Results: A positive non-significant correlation between the DNA fragment size and severity of muscle weakness was found for the forehead (r = 0.27; p = 0187), the periocular (r = 0.24; p = 0.232) and the left and right perioral (r = 0.29; p = 0.122), (r = 0.32; p = 0.085) muscles. Conclusions: Although FSHD patients exhibited a decrease in muscular activity related to the forehead, perioral, and periocular muscles the genotype–phenotype associations confirmed a weak to moderate non-significant correlation between repeat size and the severity of muscle weakness. Orofacial muscle weakening and its association with a D4Z4 contraction alone may not have the significance to serve as a prognostic biomarker, due to the weak to moderate association. Further studies with larger sample sizes are needed to determine the degree of genetic involvement in the facial growth in FSHD patients.

Cochlear function in facioscapulohumeral muscular dystrophy

OBJECTIVE

Facioscapulohumeral muscular dystrophy (FSHD) is commonly associated with high-frequency hearing impairment. Our objective was to evaluate a group of normally hearing patients with FSHD using otoacoustic emissions.

STUDY DESIGN

Prospective, randomized clinical trial.

SETTING

A tertiary University-based referral center in Athens, Greece.

PATIENTS

The study group consisted of a consecutive sample of 24 patients diagnosed on clinical, histopathologic, and genetic grounds as having FSHD. All subjects were selected on the basis of normal to near normal audiometric pure tone thresholds. Controls consisted of 40 age-matched healthy volunteers.

INTERVENTIONS

Transiently evoked otoacoustic emissions were performed. Whole reproducibility and total response were measured, as well as partial scores at the octave bands centered at 1, 2, 3, 4, and 5 kHz.

MAIN OUTCOME MEASURES

Transiently evoked otoacoustic emission measurements were compared between the two groups.

RESULTS

The audiometric findings were normal to near normal for both groups. Compared with controls, most patients had diminished scores in both whole and partial reproducibility scores and overall and partial response scores.

CONCLUSION

Despite normal hearing, subclinical involvement of the cochlea is quite common in patients with FSHD. Our findings support the genetic homogeneity of this disorder and its association with cochlear damage. Otoacoustic emissions might provide a useful tool in the clinical workup and follow-up of these patients.

Correlation between denervation activity and compound muscle action potential amplitude in hereditary motor and sensory neuropathy I and II

Studying the electrophysiological characteristics of the various types of Charcot-Marie-Tooth disease is important in the understanding of its pathophysiology. The purpose of this study was to identify the frequency of fibrillation potentials and positive sharp waves (FP/PWs) in HMSN I and II and, since they are indices of denervation, to elucidate whether they are correlated with the amplitude of compound muscle action potentials (CMAP). We reviewed the electrophysiological findings of 47 patients who have been studied in our hospital and found to suffer from Charcot-Marie-Tooth polyneuropathy. FP/PW were graded according to a 4-grade scale and the 38 m/sec criterion for motor conduction velocity (MCV) was used for distinction between HMSN I and II subgroups. Seventy percent of HMSN II patients and 81% of HMSN I patients showed fibrillation potentials in the upper or lower limbs. There was no difference in the frequency of FP/PW appearance between the two groups. In the HMSN II group the FP/PW grade correlated with CMAP amplitude in the upper limbs. In both groups there was no correlation between FP/PW grade and MCV. Our findings might indicate that in HMSN I there is a considerable axonal destruction that occurs concurrently with myelin loss.

Type II glycogenosis and thyroxine binding globulin deficiency in the same family

An eight-member family is presented with two female members suffering from the juvenile form of acid maltase deficiency (AMD), the diagnosis confirmed by biochemical study of muscle. Biochemical leucocyte investigation revealed reduced a-glucosidase activity in both patients, a brother and the parents. Endocrinological study of the family disclosed reduced levels of thyroxine binding globulin (TBG) in the father and the three daughters. We consider the co-existence of AMD and TBG deficiency interesting, as thyroxine seems to play a role in the activation of acid maltase.