Chester B. Whitley

Children with mucopolysaccharidosis: Perioperative care, morbidity, mortality, and new findings

The perioperative care, morbidity, and mortality in 30 patients with mucopolysaccharidosis (MPS) are presented. They underwent a detailed preoperative assessment and were anesthetized 141 times. An intravenous induction technique was used in most patients. It was easier to see the vocal cords, during laryngoscopy, in children with Hurler syndrome (HS) when they were younger (23 v 41 months, P < or = .01) and smaller (12 v 15 kg, P < or = .05). Preoperative obstructive breathing was associated with a significantly higher incidence of postextubation obstruction (P < or = .05). A total of 28 children underwent bone marrow transplantation (BMT); this reversed upper airway obstruction and also reversed intracranial hypertension. In children with HS, the incidence of odontoid dysplasia was 94%; 38% demonstrated anterior C1-C2 subluxation. Head and neck manipulation was limited in children with cervical spine defects. None of the 30 patients experienced spinal cord morbidity. One child suffered an intraoperative stroke; another, pulmonary edema. Severe and extensive coronary obstruction was responsible for 2 intraoperative deaths. Coronary angiography underestimated coronary artery disease.

Ocular Changes in the Mucopolysaccharidoses after Bone Marrow Transplantation: A Preliminary Report

Metabolic correction and physiologic response were evaluated after bone marrow transplantation in mucopolysaccharidosis. Eleven patients were prospectively evaluated to determine the effect of bone marrow transplantation on the progressive ocular manifestations of these disorders. Follow-up of 0.6 to 2.8 years after successful donor stem cell engraftment showed that some patients had slow clearing of the corneal clouding, reduction of intracytoplasmic inclusions in the conjunctiva, resolution of optic nerve edema, and stabilized or improved retinal function as determined by electroretinography. These preliminary results suggest that early bone marrow transplantation may alter some of the progressive ophthalmic characteristics of the mucopolysaccharidoses. Long-term follow-up is necessary to determine if these early alterations in the ocular features are predictive of a prolonged functional improvement in the visual status.

In vivo chloroquine-induced inhibition of insulin degradation in a diabetic patient with severe insulin resistance.

We report on a 26-yr-old patient with an 11-yr history of insulin-dependent diabetes mellitus who exhibited insulin resistance with a requirement of up to 15,000 U of intravenous (i.v.) insulin/day. Attempts to diminish her insulin requirement by administration of sulfated insulin or Trasylol were unsuccessful, with the patient remaining resistant to subcutaneous (s.c.) and i.v. administration of pure pork insulin. Chloroquine phosphate therapy (500 mg twice a day) resulted in a decreased requirement for i.v. insulin (700 U/day as compared with the pretreatment requirement of 8400 U/ day). Accelerated insulin degradation in s.c. fat tissue of the patient before treatment with chloroquine was demonstrated. This activity was decreased by 64% during chloroquine therapy. Inhibition of insulin degrading activity (IDA) during chloroquine therapy was associated with reductions in the leukocyte lysosomal enzymes α-galactosidase and hexosaminidase-A but not hexosaminidase-B and β-glucuronidase. This study constitutes the first reported use of chloroquine for treatment of insulin resistance as a result of accelerated insulin degradation, and it provides evidence of the effectiveness of this agent in this rare condition.

NAGLU Mutations Underlying Sanfilippo Syndrome Type B

Sanfilippo syndrome type B (mucopolysaccharidosis III B) is a rare autosomal recessive disease caused by deficiency of alpha-N-acetylglucosaminidase, one of the enzymes required for the lysosomal degradation of heparan sulfate. The gene for this enzyme, NAGLU, recently was isolated, and several mutations were characterized. We have identified, in amplified exons from nine fibroblast cell lines derived from Sanfilippo syndrome type B patients, 10 additional mutations: Y92H, P115S, Y140C, E153K, R203X, 650insC, 901delAA, P358L, A664V, and L682R. Four of these mutations were found in homozygosity, and only two were seen in more than one cell line. Thus, Sanfilippo syndrome type B shows extensive molecular heterogeneity. Stable transfection of Chinese hamster ovary cells, by cDNA mutagenized to correspond to the NAGLU missense mutations, did not yield active enzyme, demonstrating the deleterious nature of the mutations. Nine of the 10 amino acid substitutions identified to date are clustered near the amino or the carboxyl end of alpha-N-acetylglucosaminidase, suggesting a role for these regions in the transport or function of the enzyme.

Warburg syndrome: Lethal neurodysplasia with autosomal recessive inheritance

Warburg syndrome is a recently recognized autosomal recessive neurodysplasia characterized by ventricular dilation, agyria, disorganized cortical cytoarchitecture, and dysgenesis of multiple other central nervous system structures. Because the disorder is lethal, with a 25% recurrence risk, it is crucial to distinguish Warburg syndrome from nonheritable phenocopies (caused by infectious agents and other teratogens) as well as from genetic disorders with a better prognosis. The clinical presentation of a markedly depressed newborn infant with hydrocephalus or ocular anomalies should suggest the diagnosis; computed tomography may be useful to demonstrate agyria as well as ventricular dilation. However, the distinctive neuropathologic finding of absent cerebral cortical lamination associated with numerous heterotopias appears to be diagnostic. Thus brain biopsy should be considered, especially at the time of ventricular shunting, whenever the clinical presentation suggests Warburg syndrome.

Bone Marrow Transplantation for Genetic Diseases

Four recent editorials in the Journal have reviewed the potential for increasing the therapeutic armamentarium for genetic disease.1 2 3 4 Bone marrow transplantation has been considered in each of...

Light and electron microscopic features of the liver in mucopolysaccharidosis

The mucopolysaccharidosis (MPS) diseases lead to the accumulation of glycosaminoglycan in many tissues. In this study 19 MPS I, one MPS II, five MPS III, and two MPS VI patients underwent liver biopsy for light and electron microscopic examination. Electron microscopy was performed for all 27 specimens. Twenty-six specimens were studied by light microscopy, and the slides were stained with colloidal iron and alcian blue in 26 and six biopsy specimens, respectively. By hematoxylin-eosin stain 20 of 26 cases showed hepatocellular dilatation with rarefaction of the cytoplasm; the Kupffer cells were unremarkable. Twenty-four and 25 of the 26 biopsy specimens showed substantial colloidal iron staining of hepatocytes and Kupffer cells, respectively. The six biopsy specimens prepared with alcian blue stain showed no reactivity of any cell type. Electron microscopy revealed characteristic membrane-bound inclusions within the hepatocytes and Kupffer cells of all 27 biopsy specimens. Of 19 cases in which Ito cells were identified, 18 included cells containing similar inclusions. Twenty of 27 biopsy specimens also demonstrated the hepatocellular accumulation of lipid droplets. Although there were no absolute distinguishing features among the various MPS diseases, the two MPS VI cases showed glycosaminoglycan inclusions that were fewer in number, smaller, and contained more abundant lipofusion than those associated with the other MPS types.

Resolution of obstructive sleep apnea in Hurler syndrome after bone marrow transplanation

Hurler syndrome, a lethal inborn error of lysosomal metabolism, results from the systemic accumulation of glycosaminoglycan. The progressive deposition of glycosaminoglycan in tissues of the upper aerodigestive tract has been suspected as the cause of airway obstruction, and many children have required tracheostomy. In a 3-year-old patient with Hurler syndrome, polysomnography confirmed the clinical impression of obstructive sleep apnea. Biopsy of an enlarged tonsil demonstrated that more than half the tissue volume resulted from abnormal lysosomal inclusions in macrophages. Three months after transplantation, repeat testing demonstrated resolution of airway obstruction, and 6 months after transplantation, tonsil biopsy showed complete absence of lysosomal inclusions. Bone marrow transplantation produces effective metabolic correction for Hurler syndrome and may be life-saving for patients with obstructive apnea.

Evaluation of coronary artery disease in the Hurler syndrome by angiography

Hurler syndrome (mucopolysaccharidosis type I-H) is an inherited lysosomal storage disease characterized by the widespread accumulation of mucopolysaccharide in tissues throughout the body.1 Although severe coronary artery luminal narrowing has been documented by postmortem examination of the heart of patients with Hurler syndrome,2 the only reported study in which coronary angiography was performed stated that the coronary arteries appeared normal.3 As part of an ongoing protocol at our institution, selective coronary angiography was performed in children with Hurler syndrome before bone marrow transplantation. The subsequent availability of postmortem material from 3 such patients has allowed us to perform a retrospective analysis of the usefulness of selective coronary angiography in detecting the presence of coronary artery disease in patients with the Hurler syndrome.

Persistent succinylacetone excretion after liver transplantation in a patient with hereditary tyrosinaemia type I

A liver transplant was performed on a 4-year-old female in liver failure caused by hereditary tyrosinaemia, with hepatocellular carcinoma following a negative evaluation for metastases. However, serum alpha-fetoprotein levels never returned to normal after the surgery. Urinary succinylacetone (SA) was detected in her urine prior to transplantation despite strict adherence to a low-tyrosine diet. Other patients with severe liver disease awaiting liver transplantation do not excrete SA in the urine. She continued to excrete SA during the postoperative period despite normal liver functions. Oral tyrosine loading resulted in significant elevation of SA excretion. Possible explanations for this observation and clinical and therapeutic relevance are discussed.