Marjo S. van der Knaap

Multiple Carboxylase Deficiency

Biotinidase deficiency and holocarboxylase synthetase deficiency are two autosomal recessively inherited disorders of biotin metabolism affecting children below the age of two years. Both cause multiple carboxylase deficiency resulting in defects of fatty acid synthesis, gluconeogenesis and amino acid catabolism. The clinical picture involves the nervous system, the skin, the respiratory system, the digestive system and the immune system, but great individual variations often makes the clinical diagnosis difficult. Early diagnosis and treatment with biotin are essential in order to prevent death from metabolic acidosis or irreversible damage to the central nervous system. Two patients with biotinidase deficiency, two patients with holocarboxylase synthetase deficiency and a review of the literature are presented. Neonatal screening for biotinidase deficiency or a higher degree of metabolic screening of the urine in children below the age of one year with seizures and unexplained clinical course are discussed.

Mitochondrial Neurogastrointestinal Encephalomyopathy

Mitochondrial neurogastrointestinal encephalomyopathy is an autosomal recessive disease characterized by progressive ophthalmoplegia, peripheral neuropathy, mitochondrial abnormalities and gastrointestinal involvement. We describe a 19-year-old male having chronic intestinal pseudoobstruction associated with ophthalmoplegia and proximal muscle weakness. The clinical and radiologic features suggested the diagnosis of mitochondrial neurogastrointestinal encephalomyopathy. Mitochondrial genetic defects should be considered in the differential diagnosis of unexplained chronic gastrointestinal symptoms accompanied by neurological findings, especially in families where there is more than one individual with the same kind of symptoms.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, usually called CADASIL, is an inherited condition that causes stroke and other impairments. This condition affects blood flow in small blood vessels, particularly cerebral vessels within the brain. The muscle cells surrounding these blood vessels (vascular smooth muscle cells) are abnormal and gradually die. In the brain, the resulting blood vessel damage (arteriopathy) can cause migraines, often with visual sensations or auras, or recurrent seizures (epilepsy).

Leber Hereditary Optic Neuropathy

Blurring and clouding of vision are usually the first symptoms of LHON. These vision problems may begin in one eye or simultaneously in both eyes; if vision loss starts in one eye, the other eye is usually affected within several weeks or months. Over time, vision in both eyes worsens with a severe loss of sharpness (visual acuity) and color vision. This condition mainly affects central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. Vision loss results from the death of cells in the nerve that relays visual information from the eyes to the brain (the optic nerve). Although central vision gradually improves in a small percentage of cases, in most cases the vision loss is profound and permanent.