Lipoprotein disorder, cirrhosis, and olivopontocerebellar degeneration in two siblings

Congenital disorder of glycosylation type Ia: heterogeneity in the clinical presentation from multivisceral failure to hyperinsulinaemic hypoglycaemia as leading symptoms in three infants with phosphomannomutase deficiency

We describe three patients with congenital disorder of glycosylation (CDG) type Ia, all of whom had persistent hyperinsulinaemic hypoglycaemia responding to diazoxide therapy as a common feature. The first patient, an infant girl, presented with recurrent vomiting, failure to thrive, liver impairment, hypothyroidism and a pericardial effusion. The second patient, also female, had a milder disease with single organ involvement, presenting as isolated hyperinsulinaemic hypoglycaemia, not associated with any cognitive impairment. The third patient, a boy presented with multi-organ manifestations including congenital hypothyroidism, persistent hyperinsulinaemic hypoglycaemia, coagulopathy, olivopontocerebellar hypoplasia and recurrent pancreatitis. All three patients had a type 1 serum transferrin isoform pattern, and were subsequently found to have low phosphomannomutase activity, confirming the diagnosis of CDG type Ia. Our findings emphasize that CDG should be considered as a differential diagnosis in patients with persistent hyperinsulinaemic hypoglycaemia and that it may even occasionally be the leading symptom in CDG Ia.

Juvenile global tremor: a clinicopathologic syndrome mimicking polymyoclonia

Olivary nucleus degeneration is one of the pathologic characteristics of infantile olivopontocerebellar atrophy. It has also been described in premature neonates and infants with severe perinatal asphyxia and is thought to represent retrograde transsynaptic changes from cerebellar hemisphere lesions. A 2-year-old boy developed global tremor after a respiratory infection with remission after corticosteroid therapy, and recurrence of the tremor during gradual withdrawal of steroids. Neuropathologic examination revealed neuronal loss and gliosis in the lateral portions of both inferior olivary nuclei without associated abnormalities in the cerebellum. This appears to be a unique case, both clinically and neuropathologically.

Autopsy case of acute encephalopathy linked to familial hemiplegic migraine with cerebellar atrophy and mental retardation

A 19-year-old female patient, who had exhibited esotropia, mild cerebellar ataxia, mild mental retardation, and cerebellar atrophy on magnetic resonance images at the age of 15, developed signs of acute encephalopathy, and thereafter died of disseminated intravascular coagulation on the day of her admission. Both her mother and sister suffered from attacks of hemiplegic migraine, mild mental retardation, and cerebellar ataxia. Neuropathological examinations revealed acute changes in the widespread cerebral cortex, chronic degenerative changes in the anterior lobe of the cerebellar vermis, axonal spheroids in the Goll's nucleus, pseudo-calcinosis in the globus pallidus, and glial bundles in the cranial nerves. The most fascinating features were changes of Purkinje cells, such as cactuses (asteroid bodies, dendritic expansions), somatic sprouts, and torpedoes. These changes may be characteristic of familial hemiplegic migraine with cerebellar atrophy, as well as the other metabolic diseases, such as Menkes' kinky hair disease, infantile (Tay-Sachs type) amaurotic idiocy, organic mercury intoxication, and mitochondrial encephalopathy, of which cases often exhibit such pathological changes of Purkinje cells. Therefore, familial hemiplegic migraine may share some metabolic abnormalities with the diseases mentioned above.

Congenital disorders of glycosylation

Congenital disorders of glycosylation (CDG) are a rapidly growing group of genetic diseases that are due to defects in the synthesis of glycans and in the attachment of glycans to other compounds. Most CDG are multisystem diseases that include severe brain involvement. The CDG causing sialic acid deficiency of N-glycans can be diagnosed by isoelectrofocusing of serum sialotransferrins. An efficient treatment, namely oral D-mannose, is available for only one CDG (CDG-Ib). In many patients with CDG, the basic defect is unknown (CDG-x). Glycan structural analysis, yeast genetics, and knockout animal models are essential tools in the elucidation of novel CDG. Eleven primary genetic glycosylation diseases have been discovered and their basic defects identified: six in the N-glycan assembly, three in the N-glycan processing, and two in the O-glycan (glycosaminoglycan) assembly. This review summarizes their clinical, biochemical, and genetic characteristics and speculates on further developments in this field.

Missense mutations in the phosphomannomutase 2 gene of two Japanese siblings with carbohydrate-deficient glycoprotein syndrome type I

Carbohydrate-deficient glycoprotein syndrome type I (CDG1) is an autosomal recessive disorder characterized by severe nervous system involvement and a carbohydrate moiety deficiency in N-linked glycoproteins. Clinical symptoms are psychomotor retardation, stroke-like episodes or hemorrhagic episodes, hepatic dysfunction, polyneuropathy, and cerebellar ataxia. Marked atrophy of the cerebellar hemispheres and pons is recognizable on CT scan or MRI. CDGI has been mapped to human chromosome 16p by linkage studies. Recently, missense mutations in the gene for phosphomannomutase (PMM2) have been detected in Caucasian patients with CDG1. We studied DNA mutations in PMM2 in a Japanese family with CDG1. DNA sequencing of PMM2 in the siblings showed missense mutations of maternal origin in exon 5 and of paternal origin in exon 8. No such mutations were detected in 50 unrelated healthy Japanese. These findings suggest that the PMM2 is responsible for CDG1 in the Japanese as well as in Caucasians, and CDG1 may be the diagnosis in OPCA of neonatal onset, more often than currently thought.

Familial infantile olivopontocerebellar atrophy

Infantile olivopontocerebellar atrophies are rare progressive, fatal, neurologic conditions characterized pathologically by loss of neurons and gliosis in the cerebellum, pons, and inferior olivary nuclei in early life. The clinical and pathologic features of 2 brothers who presented in early infancy with failure to thrive and neurologic deterioration leading to death by the age of 5 months are reported. Magnetic resonance imaging of the brain of Patient 1 disclosed progressive pontocerebellar atrophy. Both siblings had identical patterns of neuronal loss consistent with olivopontocerebellar atrophy at postmortem examination. Serum biochemical abnormalities of low thyroid binding globulin, hypoalbuminemia, and low cholesterol, suggestive of the carbohydrate-deficient glycoprotein syndrome, were also present in both patients.

A variant form of hypobetalipoproteinaemia associated with ataxia, hearing loss and retinitis pigmentosa

A six-year-old Japanese boy had ataxia, mental retardation, peripheral neuropathy, proximal myopathy, hearing loss, retinitis pigmentosa and deficiencies in apolipoprotein AI, B, CII and CIII. His clinical features except for hearing loss resembled those of abetalipoproteinaemia or symptomatic hypobetalipoproteinaemia, but his apolipoprotein abnormalities were distinct from these disorders. He had apolipoprotein B-100 with a normal molecular weight. Although most of his neurological manifestations were compatible with those of vitamin E deficiency, their early onset and the presence of hearing loss was unusual for that condition. There has been slight deterioration of ataxia during two years follow-up despite high-dose vitamin E supplementation. Other abnormalities in lipid metabolism might be associated with the neurological damage in this case.

Carbohydrate-deficient glycoprotein syndrome with previously unreported features

A boy with carbohydrate-deficient glycoprotein syndrome died at five months of age in status epilepticus. Postmortem examination failed to show the classically observed olivopontocerebellar atrophy. Two previously unreported features were present: cataracts from the first week of life and lysosomal storage affecting mainly the anterior horn neurons of the spinal cord.

Cholesterol metabolism in the RSH/Smith-Lemli-Opitz syndrome: summary of an NICHD conference

During the evolution of multicellularity and attendant processes of development, cholesterol played a key role in the formation of the plasma membrane and outer mitochondrial membrane of every cell in the organism. Later functions include pivotal involvement in steroid, bile acid, and vitamin D metabolism and myelination of the nervous system. In the CNS myelination does not begin until the third trimester, and subcortical myelination not until after birth. The cholesterol of the cell membrane of the ovum is maternally derived. It is not known when the zygote begins making its own cholesterol during morphogenesis and histogenesis, but it must occur early to keep up with the dramatic rate of cell division in the embryo. Thus, it is a startling surprise that human embryos and fetuses apparently able to synthesize little cholesterol (because of a presumed defect of the delta 5,7-sterol, delta 7-reductase that converts 7-dehydrocholesterol (7-DHC) into cholesterol) frequently live to term and, rarely, may be so mildly affected as to attend school with only mild MR. The discovery by G. Stephen Tint and his co-workers of the apparent 7-DHC reductase deficiency makes the RSH (Smith-Lemli-Opitz) syndrome the first true metabolic malformation syndrome. A teratological animal model which has been known for 30 years now appears applicable to the RSH/SLO syndrome. A multidisciplinary NICHD conference held on September 20-21, 1993 reviewed the numerous implications of this discovery and agreed unanimously that research in this field be given highest priority in order to better understand cholesterol synthesis in the mammalian brain, cholesterol transport from mother to embryo and fetus, pre- and postnatal metabolic compensation in structure and function for a profound block in cholesterol synthesis, the nature of the blood-brain barrier for cholesterol, treatment of affected infants, children, and adults, structure and genetic specification of a 7-DHC reductase enzyme (which has never been purified!) and its evolution, the variability of the syndrome and whether it is genetically homo- or heterogeneous, the population genetics of the RSH syndrome, possible selective advantages (or disadvantages) of heterozygotes, and means of newborn screening, carrier detection, and prenatal diagnosis.

Inherited syndrome of infantile olivopontocerebellar atrophy, micronodular cirrhosis, and renal tubular microcysts: review of the literature and a report of an additional case

An 8-month-old male infant who presented in the neonatal period with failure to thrive, bilateral pleural and pericardial effusions, and hepatic insufficiency characterized by elevated liver functions tests and hypoalbuminemia was found at autopsy to have an unusual combination of olivopontocerebellar atrophy (OPCA), micronodular cirrhosis, and renal tubular microcysts. Metabolic evaluation was significant only for elevated urine dicarboxylic acids. In the brain, sections from the cerebellum showed marked atrophy of folia most severe in the vermal and paravermal regions. In addition, mild neuronal loss was present in the basis pontis and inferior olivary nuclei accompanied by gliosis. Residual Purkinje cells in the cerebellar hemispheres exhibited greatly expanded and swollen arbors, which ultrastructurally were found to contain densely packed membranous cytoplasmic body-like inclusions that had the appearance of unwinding, lamellar coils. Review of the literature shows that this constellation of findings has been associated with carbohydrate-deficient transferrin. This biochemical marker along with the distinctive clinical presentation and pathological features clearly delineates a unique subset of OPCA.

Fatal infantile encephalopathy with olivopontocerebellar hypoplasia and micrencephaly. Report of three siblings

We report three siblings born with severe neonatal encephalopathy, manifested clinically by microcephaly, myoclonus, and muscular hypertonus. Karyotypic analyses and all biochemical investigations were unrevealing. All three patients died during infancy. Postmortem examination of the brain in one child disclosed severe neuronal loss in the inferior olives and the pontine nuclei. There was also severe hypoplasia of the cerebellum and micrencephaly. There was diffuse gliosis of the white matter in all areas of the brain. We believe this may represent a previously undescribed form of familial infantile encephalopathy with olivopontocerebellar hypoplasia.

Hypertrophic obstructive cardiomyopathy in a neonate with the carbohydrate-deficient glycoprotein syndrome

The carbohydrate-deficient glycoprotein (CDG) syndrome in its most severe form (neonatal olivopontocerebellar atrophy) is a life-threatening multisystem disease. We report a neonate who was referred for cardiological assessment because of respiratory distress, a murmur and episodes of desaturation. After initial spontaneous improvement he presented at 9 weeks with evidence of a severe hypertrophic obstructive cardiomyopathy (HOCM). The diagnosis of CDG syndrome was suggested by the characteristic dysmorphic features, hypotonia, visual inattention and severe failure to thrive; it was confirmed by electrophoresis of serum transferrin. HOCM can be a feature of the CDG syndrome, in addition to the (previously reported) pericardial effusions.

Olivopontocerebellar atrophy of neonatal onset and disialotransferrin developmental deficiency syndrome

Two brothers presented with olivopontocerebellar atrophy of neonatal onset. The clinical features (failure to thrive, hypotonia, liver disease, effusions, and visual inattention) were similar to those of the four cases already reported, as were the necropsy findings of olivopontocerebellar atrophy, hepatic steatosis and fibrosis, and microcystic renal changes. The clinical similarities between this and the disialotransferrin developmental deficiency syndrome were noted. The characteristic abnormality of serum transferrin found in the latter syndrome was also found in the two cases reported here. We suggest that both syndromes are caused by the same, or related, defects in glycoprotein metabolism.

Neurophysiological and neuropathological studies in two children with unusual form of multiple system degeneration: evidence for cerebellar and brainstem involvement

Comparative neurophysiological and neuropathological studies were performed in two children who were found as a very rare multiple system degeneration (MSD) in brainstem and cerebellum. One young child suffered from both multiple system and retinal degeneration and another child had widespread multiple system degeneration associated with lipoprotein disorder and liver cirrhosis. The results of the neurophysiological studies indicated dysfunction of the brainstem and the peripheral nerves and were well correlated with the clinical course. CT studies showed progressive cerebellar atrophy. Since serial neurophysiological and CT studies were compatible with the neuropathological findings, the combination of these examinations seems to be quite valuable for understanding the pathogenesis and monitoring the progression of MSD in childhood.