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CARDIOVASCULAR JOURNAL OF AFRICA • Vol 26, No 5, October/November 2015
14
AFRICA
2
US/MRC Centre for TB Research, University of Stellenbosch,
South Africa
Background:
The minimum criterion for the diagnosis of hyper-
trophic cardiomyopathy (HCM) is thickening of the left ventric-
ular wall, typically in an asymmetrical or focal fashion, and it
requires no functional deficit. Using this criterion, we identified
a family with four affected individuals and a single unrelated
individual essentially with restrictive cardiomyopathy (RCM).
Mutations in genes coding for the thin filaments of cardiac
muscle have been described in RCM and HCM with ‘restric-
tive features’. One such gene encodes for cardiac troponin I
(
TNNI3
), a sub-unit of the troponin complex involved in the
regulation of striated muscle contraction. We hypothesised that
mutations in
TNNI3
could underlie this particular phenotype,
and we therefore screened
TNNI3
for mutations in 115 HCM
probands.
Methods:
Clinical investigation involved examination, echocar-
diography, chest X-ray and an electrocardiogram of both the
index cases and close relatives. The study cohort consisted of
113 South African HCM probands, with and without known
founder HCM mutations, and 100 ethnically matched control
individuals. Mutation screening of
TNNI3
for disease-causing
mutations were performed using high-resolution melt (HRM)
analysis.
Results:
HRM analyses identified three previously described
HCM-causing mutations (p.Pro82Ser, p.Arg162Gln,
p.Arg170Gln) and a novel exonic variant (p.Leu144His). A
previous study involving the same amino acid identified a
p.Leu144Gln mutation in a patient presenting with RCM, with
clinical features of HCM. We observed the novel p.Leu144His
mutation in three siblings with clinical RCM and varying degrees
of ventricular hypertrophy. The isolated index case with the
de
novo
p.Arg170Gln mutation presented with a similar phenotype.
Both mutations were absent in a healthy control group.
Conclusion:
We have identified a novel disease-causing
p.Leu144His mutation and a
de novo
p.Arg170Gln mutation
associated with RCM and focal ventricular hypertrophy, often
below the typical diagnostic threshold for HCM. Our study
provides information regarding
TNNI3
mutations underlying
RCM in contrast to other causes of a similar presentation, such
as constrictive pericarditis or infiltration of cardiac muscle,
all with marked right-sided cardiac manifestations. This study
therefore highlights the need for extensive mutation screening
of genes encoding for sarcomeric proteins, such as
TNNI3
to
identify the underlying cause of this particular phenotype.
PULMONARY HYPERTENSION IN A RURAL AREA:
PREVALENCE,
CORRELATES
AND
CLINICAL
FEATURES FROM THE SHISONG CARDIAC CENTRE,
CAMEROON
Dzekem Bonaventure Suiru
1
, Dzudie Anastase*, Tantchou
Tchoumi Cabral,
2
Aminde Leopold
3
, Mocumbi Ana O
4
, Abanda
Martin
1
, Kengne Andre Pascal
5
, Thienemann Friedrich
6
, Sliwa
Karen
7
1
Faculty of Health Sciences, University of Buea, Cameroon;
Clinical Research Education, Networking and Consultancy,
Douala, Cameroon
*Faculty of Health Sciences, University of Buea, Cameroon;
Clinical Research Education, Networking and Consultancy,
Douala, Cameroon; Cardiology Unit, Douala General Hospital,
Douala, Cameroon; Department of Medicine, Faculty of Health
Sciences, University of Cape Town, Cape Town, South Africa
2
Shisong Cardiac Centre, Kumbo, Cameroon
3
Clinical Research Education, Networking and Consultancy,
Douala, Cameroon
4
Faculty of Medicine, Eduardo Mondlane University, Maputo,
Mozambique
5
Department of Medicine, Faculty of Health Sciences, University
of Cape Town, Cape Town, South Africa; Non-communicable
Diseases Unit, South African Medical Research Council, South
Africa
6
Department of Medicine, Faculty of Health Sciences,
University of Cape Town, Cape Town, South Africa; Clinical
Infectious Diseases Research Initiative, Institute of Infectious
Diseases and Molecular Medicine, Faculty of Health Science,
University of Cape Town, Cape Town, South Africa
7
Department of Medicine, Faculty of Health Sciences, University
of Cape Town, Cape Town, South Africa; Hatter Institute for
Cardiovascular Research in Africa, Faculty of Health Sciences,
University of Cape Town, Cape Town, South Africa
Introduction:
Pulmonary hypertension (PH) is a devastating,
progressive disease with increasingly debilitating symptoms and
eventually death due to narrowing of the pulmonary vasculature
and consecutive right heart failure. The epidemiology of PH in
low- to middle-income countries is unknown, but recent data
suggest a high prevalence on the African continent. We assessed
the prevalence and characteristics of PH in patients attending
the rural cardiac centre of Shisong, Cameroon.
Methods:
The current study forms part of the ongoing
Pan-African Pulmonary Hypertension Cohort (PAPUCO)
study. From September 2013 to December 2014, all consecu-
tive patients with newly diagnosed PH were prospectively
recruited. PH was diagnosed in patients with clinical suspicion
and echographically measured right ventricular systolic pressure
(RVSP)
>
35 mmHg. PH was classified as mild (RVSP: 36–50
mmHg), moderate (RVSP: 51–60 mmHg) and severe (RVSP:
>
60 mmHg).
Results:
Out of 2 194 patients who had echocardiograms done,
343 had PH (15.6%). In all, 150 (mean age 62.7
±
18.7 years,
54.7% women) were included in these analyses. Overall mean
RVSP was 68.6 mmHg, and 7.3, 29.3 and 63.3% presented
with mild, moderate and severe PH, respectively. PH due to
left heart disease (PHLHD) was the commonest type of PH
(64.7%), with rheumatic valvular heart disease accounting
for 36.1%. Body mass index, respiratory rate, left ventricu-
lar end-systolic and -diastolic diameters positively correlated
with RVSP, while oxygen saturation negatively correlated with
RVSP. Co-morbidities at presentation included indoor smoke
from cooking (80.7%), hypertension (52.0%), family history
of cardiovascular disease (50.0%), diabetes (31.3%), alcohol