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. 2020 Aug;8(8):e1362.
doi: 10.1002/mgg3.1362. Epub 2020 Jun 15.

DMD-related muscular dystrophy in Cameroon: Clinical and genetic profiles

Edmond Wonkam-Tingang  1 , Séraphin Nguefack  2   3 , Alina I Esterhuizen  1   4 , David Chelo  2   5 , Ambroise Wonkam  1   6
Affiliations

DMD-related muscular dystrophy in Cameroon: Clinical and genetic profiles

Edmond Wonkam-Tingang et al. Mol Genet Genomic Med. 2020 Aug.

Abstract

Background: Most of the previous studies on Duchenne Muscular Dystrophy (DMD) were conducted in Caucasian, Asian, and Arab populations. Therefore, little is known about the features of this disease in Africans. In this study, we aimed to determine the clinical characteristics of DMD, and the common mutations associated with this condition in a group of Cameroonian patients.

Methods: We recruited DMD patients and performed a general physical examination on each of them. Multiplex ligand-dependant probe amplification was carried out to investigate exon deletions and duplications in the DMD gene (OMIM: 300377) of patients and their mothers.

Results: A total of 17 male patients from 14 families were recruited, aged 14 ± 5.1 (8-23) years. The mean age at onset of symptoms was 4.6 ± 1.5 years, and the mean age at diagnosis was 12.1 ± 5.2 years. Proximal muscle weakness was noted in all patients and calf hypertrophy in the large majority of them (88.2%; 15/17). Flexion contractures were particularly frequent on the ankle (85.7%; 12/14). Wasting of shoulder girdle and thigh muscles was present in 50% (6/12) and 46.2% (6/13) of patients, respectively. No patient presented with hearing impairment. Deletions in DMD gene (OMIM: 300377) occurred in 45.5% of patients (5/11), while duplications were observed in 27.3% (3/11). Both mutation types were clustered between exons 45 and 50, and the proportion of de novo mutation was estimated at 18.2% (2/11).

Conclusion: Despite the first symptoms of DMD occurring in infancy, the diagnosis is frequently made later in adolescence, indicating an underestimation of the number of cases of DMD in Cameroon. Future screening of deletions and duplications in patients from Cameroon should focus on the distal part of the gene.

Keywords: Africa; Cameroon; Duchenne muscular dystrophy; clinical patterns; genetics.

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Conflict of interest statement

We declare that no competing interests exist.

Figures

FIGURE 1
FIGURE 1
Distribution of our study population according to age range (years). N = 17 patients
FIGURE 2
FIGURE 2
Clinical signs at onset of the disease. N = 17 patients
FIGURE 3
FIGURE 3
Inheritance pattern of DMD in our cohort. (a) Pedigree of a multiplex family (family 5), suggestive of X‐linked inheritance. The proband here has a cousin who exhibits clinical signs of DMD, and a deceased uncle who has presented the same clinical signs. (b) Pedigree of a family (family 9) in which the disease seems to be of sporadic occurrence. Arrows indicate the proband
FIGURE 4
FIGURE 4
Distribution of the nature of mutations in patients according to affected exons
See this image and copyright information in PMC

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