Other Important Findings by System
Cardiac
- Congestive heart failure
- Risk of serious arrhythmia, including sudden cardiac death
- Left ventricle non-compaction
- Hypertrabeculation or deepened trabeculations of the heart
- Loss of cross-striations of the heart
- Septal defects
- Endocardial Fibroelastosis
Neurological
Neurological assessment is generally normal with exception of muscle weakness and its consequences, such as decreased stretch reflexes or strabismus. The intellect of children with Barth syndrome is normal. Commonly, children with Barth syndrome are reported to be globally delayed, but more often than not, most of the disability is motor and not cognitive in nature. Mild to moderate learning disabilities have been associated with visual-spatial and arithmetic reasoning [Mozzocco et al (2001)]12.
A floppy infant or child may be referred to the neurologist without any other relevant background information, and may actually have:
- Cardioskeletal myopathy
- Lipid myopathy
- 3-methylgultaconic aciduria (Type II)
A child may also present in the pediatric neurology setting through a referral from another sub-specialist prior to or subsequent to a diagnosis. The child with Barth syndrome could easily present for an array of reasons.
Neuromuscular symptoms of Barth syndrome:
- Muscle involvement mainly in a limb girdle distribution
- Under-developed muscle mass
- Moderate weakness, permitting unsupported walking
- Exercise intolerance, lack of stamina unrelated to cardiac disease
- Absence of contractures
- No involvement of bulbar musculature, with the exception of occasional mild facial weakness
- No involvement of extra-ocular muscles or diaphragm
- Positive Gowers’ sign [please see “Neurological Diagnostic Criteria for Barth Syndrome Presentation” below]
- Delayed gross motor development in early childhood
- Fatigue: (NOTE: in some cases quite severe) This symptom may be chronic; rapid exhaustion upon exertion
- Skeletal muscle weakness and hypotonia (NOTE: Hypotonia is frequently reported as the earliest symptom either in the newborn or neonate period. Muscle mass is markedly reduced in most children which also contributes to the appearance of failure-to-thrive.)
- Pain: Abdominal and Headaches
- Waddling gait
View Presentation: Neurological Diagnostic Criteria for Barth Syndrome.
Gastrointestinal
- Frequent diarrhea or constipation
Immunology/Haematology
- Recurrent aphthous ulcers: Not always relative with neutropenia; however, the risk of secondary infection should not be underappreciated. These ulcers are painful lesions. Feeding difficulties may be encountered during eruptions. Size, frequency, severity and number vary.
- Recurrent focal or systemic infections: These can cause life-threatening infections during the early years of life [Barth et al (1983)1].
Metabolism
- Feeding problems: In some cases assistive feeding devices are required.
- Cardiolipin deficiency: The defective remodeling of cardiolipin affects the inner membrane and integrity of the mitochondria. [view image: About Barth Syndrome: Myocardial mitochondrion.]
Endocrine
- Hypoglycemia: Including fasting hypoglycemia in newborn period.
- Low bone density: Severity ranges from osteopenia to osteoporosis.
- Growth delays: Abnormal growth pattern that parallels constitutional growth delay, but with greater severity (short stature in early years, followed by accelerated growth rate in late puberty)
Other Characteristics
Isolated malformations have been observed with an unusually high frequency (up to 25% of patients). Collectively, these do not suggest any known malformation mechanism, but their diversity is surprising.
Out of a total of 23 patients in 2002, the following malformations were found by history or examination {# patients}:
- Postaxial polydactyly (hand and foot) {1}
- Bilateral iris colobomas {1}
- Preauricular skin tags {6}
- Dermoid cyst of the orbit {1}
- Persistent urachus {1}
- Multiple congenital pigmented nevi {6}
- Transposition of the great arteries {2}
- Large or multiple VSDs {5}
In addition, about 25% of patients have abnormal left ventricular trabeculation or frank non-compaction of the left ventricle.
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