Facioscapulohumeral Dystrophy
Facioscapulohumeral dystrophy (FSHD) is an autosomal dominant disorder resulting in characteristic pattern of muscular weakness. Weakness mainly affects facial and upper girdle muscles, going on to lower girdle, as disease advances. Scapular winging and r
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Facioscapulohumeral Dystrophy
6.1
Introduction
Facioscapulohumeral dystrophy (FSHD) is characterised by progressive muscle weakness and wasting exhibiting a clinical pattern evident from early stages of the disease. It affects facial, periscapular and humeral muscles early in the disease course, a constellation which is not commonly seen in other myopathies (Tawil 2006). The progression can be marked by periods of rapid deterioration followed by stabilisation (Stübgen and Stipp 2010). FSHD is inherited as autosomal dominant disease; however, up to 30% cases are sporadic, arising from de novo mutations (Tawil et al. 2015).
6.2
Epidemiology
Two French physicians – Landouzy and Dejerine – initially described a family with progressive wasting disorder, probably giving the early description of FSHD (Landouzy and Dejerine 1885). The prevalence of FSHD is 1 in 20,000 individuals worldwide (Padberg 2004).FSHD is the third most common form of muscular dystrophy. It accounts of 2–3% cases of muscular dystrophy in India (Khadilkar 2008). The median age of onset of FSHD is around 17 years, but with a wide range varying at the most extreme from infancy to the seventh decade (Tawil et al. 2015). A significant variability in clinical expression is present, even amongst affected members of the same family.
6.3
Clinical Features
There are three characteristics of the distribution of muscle weakness in FSHD (Table 6.1):
© Springer Nature Singapore Pte Ltd. 2018 S.V. Khadilkar et al., Neuromuscular Disorders, https://doi.org/10.1007/978-981-10-5361-0_6
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6 Facioscapulohumeral Dystrophy
Table 6.1 Clinical features of FSHD Site of involvement Facial involvement
Upper limb
Clinical features As many as two thirds of patients are unaware of facial involvement (Walton and Nattrass 1954). The most evidently affected muscles are orbicularis oculi and orbicularis oris Difficulty closing the eyes – sleeping with eyes open leads to dryness, uncomfortable feeling and gritty eyes in the mornings Slight staring appearance without proptosis in awake state Difficulty to whistle, suck or blow balloons. Most patients never realise the link between these mild inconveniences and later development of shoulder weakness. Asymmetric facial involvement is common and most evident on smiling Difficulty in abducting arms with resultant difficulty in keeping objects on to high shelves, difficulty in combing hair and easy fatigue The main muscles involved are the latissimus dorsi, serratus anterior, pectoralis, rhomboids, trapezius, supraspinatus, infraspinatus and deltoid Asymmetric winging of scapula The shoulders tend to slope forward with straight clavicles and pectoral muscle atrophy. The characteristic pattern causes chicken wing scapulae for which at times medical attention is sought
Lower limb involvement
Typical affection of peroneal compartment presenting as asymmetric foot drop
Abdominal muscles
Protuberance of the abdomen and exaggerated lumbar lordosis
Facial wasting Unlined face Mild stare Sometimes facial weakness
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