IMPORTANCE OF 6-MINUTE WALK TEST IN DIAGNOSTICS OF RARE METABOLIC MYOPATHY - A CASE REPORT OF CARNITINE PALMITOYLTRANSFERASE II DEFICIENCY
Journal
Архиви на јавно здравје = Archives of public health
Date Issued
2017-12
Author(s)
Angelkova Natalija
Sabolich Vesna
Mandjukovska Hristina
Abstract
Diagnosis of rare inherited neuromuscular disorders is sometimes delayed due to variations in
time of onset, different clinical appearance and limited diagnostic possibilities. The management
of patients starts with neurological examination, followed by specific laboratory tests and
neurophysiologic assessment. In the era of molecular medicine, molecular biology tools are
useful in avoiding some of the invasive investigations such as muscle biopsy. We present a boy
with a mild form of metabolic myopathy due to carnitine palmitoyltransferase 2 deficiency
diagnosed upon timed functional assessment. A child had delayed developmental milestones,
associated with fatigue and muscle pain during exercising and longer walks. There were no
episodes of myoglobinuiria during exercise or during febrile illnesses. Neurological examination
reveled proximal muscle weakness. Serum creatine kinase (CK) and serum lactate were above
normal limits. Serum acylcarnitine profile was normal. Short timed functional tests such as
10 meters walk/run test showed normal results. Nord Star Ambulatory Assessment showed
difficulties in balance and jumping. Diagnosis of myopathy was suspected after performance of
6-minute walk test, when the passed distance was 327 meters with slowing and fatigue. EMG and
echocardiography were within normal range. Diagnosis was established by sequencing of the CPT
II gene which revealed c.338C>T (p.Ser113Leu) mutation in homozygous form as characteristic
CPT II deficiency profile.
time of onset, different clinical appearance and limited diagnostic possibilities. The management
of patients starts with neurological examination, followed by specific laboratory tests and
neurophysiologic assessment. In the era of molecular medicine, molecular biology tools are
useful in avoiding some of the invasive investigations such as muscle biopsy. We present a boy
with a mild form of metabolic myopathy due to carnitine palmitoyltransferase 2 deficiency
diagnosed upon timed functional assessment. A child had delayed developmental milestones,
associated with fatigue and muscle pain during exercising and longer walks. There were no
episodes of myoglobinuiria during exercise or during febrile illnesses. Neurological examination
reveled proximal muscle weakness. Serum creatine kinase (CK) and serum lactate were above
normal limits. Serum acylcarnitine profile was normal. Short timed functional tests such as
10 meters walk/run test showed normal results. Nord Star Ambulatory Assessment showed
difficulties in balance and jumping. Diagnosis of myopathy was suspected after performance of
6-minute walk test, when the passed distance was 327 meters with slowing and fatigue. EMG and
echocardiography were within normal range. Diagnosis was established by sequencing of the CPT
II gene which revealed c.338C>T (p.Ser113Leu) mutation in homozygous form as characteristic
CPT II deficiency profile.
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