Shwachman's syndrome. A review of 21 cases

Aberrant phagocyte function in Shwachman syndrome

Polymorphonuclear leucocytes (PMN) of patients with Shwachman syndrome show impaired mobility in vitro. We took this finding a step further by studying chemotaxis and chemiluminescence responses of purified PMN and monocytes (MO) of seven patients with Shwachman syndrome. Chemiluminescence responses of the patients' PMN were significantly increased, and thus impaired mobility may have derived from auto-oxidation of PMN. Chemotaxis of purified PMN was not impaired in a membrane filter, but it did become impaired when PMN were remixed with autologous mononuclear (MN) cells or MO. These cells always increased the migration of PMN. Because the patients' cells were fully capable of increasing the migration of control PMN, the defect most probably involved PMN. This is in harmony with the finding that the patients' purified PMN showed depressed chemotaxis under agarose. This suggests that for detecting impaired chemotaxis of purified PMN the assay conditions were more optimal in the agarose test than in the filter test. Both chemotaxis and chemiluminescence responses of the patients' MO were depressed, and thus, the defects involving PMN and MO are separate.

Pancreatic exocrine aplasia, clinical features of leprechaunism, and abnormal gonadotropin regulation

A female infant displaying morphological and clinical abnormalities is described. She had severe developmental delay, intrauterine growth retardation, and failure to thrive. Her features included an elfin facies, body and facial hirsutism, buttonlike nipples and prominent clitoris and labia. Endocrinological evaluation revealed markedly elevated serum gonadotropin levels. An LHRH stimulation test showed no LH response to LHRH but a rapid and pronounced FSH response. The patient died at 13 months following a respiratory infection. Postmortem examination revealed normal pituitary histology but an unusual pancreatic histology characterized by total absence of acinar cells. This patient had features suggestive of several clinical syndromes including leprechaunism, Shwachman syndrome, and Johanson-Blizzard syndrome, none of which, was completely satisfied. It is concluded that the infant may represent an atypical case of leprechaunism or a previously undescribed syndrome.

Renal tubular acidosis in a case of Shwachman's syndrome

We describe metabolic acidosis in a 15-month-old girl with clinical features of Shwachman's syndrome. Renal function tests indicated that the patient had type 1 renal tubular acidosis. Based on our findings and other reports of renal tubular dysfunction in patients with Shwachman's syndrome, we conclude that it is important to look for a possible renal tubular defect in this syndrome.

Glycogen accumulation in the pars recta of the proximal tubule in Fanconi syndrome

We reviewed the renal pathology in 10 cases of renal Fanconi syndrome. Five cases showed the Armanni-Ebstein lesion, i.e., clear glycogen-filled cells limited to the pars recta of the proximal tubules. The 5 cases included 2 siblings with a unique syndrome characterized by death in infancy, severe Fanconi syndrome, severe rickets, carnitine deficiency, and atrophy of the exocrine pancreas. Two other siblings had glycogen storage disease type XI. One of 4 cases of putative tyrosinemia had the lesion. The ultrastructure was studied in 2 cases. The Armanni-Ebstein lesion in these cases was morphologically indistinguishable from that seen in diabetic patients dying after prolonged hyperglycemia. Glycosuria is the only common factor in both diabetic hyperglycemia and the varied proximal tubular diseases studied. The mechanism of the glycogen accumulation in this short parts recta segment of the proximal renal tubule was further investigated by reviewing the renal histology in cases of glycogen storage disease types I, II, III, and VIII. None showed the Armanni-Ebstein lesion, but type I showed glycogen deposition throughout the proximal tubule. Thus, the Armanni-Ebstein lesion is not the result of an enzymatic deficiency for glycogen synthesis in the convoluted tubules.

Central pontine myelinolysis in a child with the Shwachman-Diamond syndrome

The first case of central pontine myelinolysis in a child with the Shwachman-Diamond syndrome is reported. Marked fluctuation of serum glucose and sodium levels, but no hyponatremia, was observed throughout the patient's hospital course. Both of these abnormalities may have contributed to the development of the lesion. Liver abnormalities, implicated in other pediatric cases of central pontine myelinolysis, were also observed.

Frequent myocardial lesions in Shwachman's syndrome. Eight fatal cases among 16 Finnish patients

A total of 16 children with Shwachman's syndrome were studied over a period of 17 years. Eight cases were detected in autopsy at 6 to 15 months; all had died of cardiac failure due to myocardial lesions. The left ventricles showed necrosis of myofibres in large areas and the pancreas was atrophic and replaced by adipose tissue. The other eight patients included two siblings of deceased cases. Only one of these showed transient cardiac failure and no significant nutritional deficiencies were found. They had steatorrhoea due to failure of the exocrine pancreas and either constant (6 cases) or cyclic (2 cases) neutropenia. The steatorrhoea improved with age. Pyogenic infections, mainly otitis media were frequent during the first three years of life. Measurements of humoral and cell-mediated immunity were normal, but in addition to low numbers of neutrophils, the neutrophilic chemotaxis was depressed in all seven patients tested. Skin lesions, hepatic inflammation, and growth tended to improve with age. The family data of the patients is consistent with an autosomal recessive trait inheritance.

Constant defect in neutrophil locomotion but with age decreasing susceptibility to infection in Shwachman syndrome

Chemotaxis, phagocytosis and bactericidal activity of neutrophils obtained from eight patients with Shwachman syndrome were studied repeatedly over a 9 year period. In a membrane filter the patient neutrophils migrated both toward casein and toward zymosan activated serum significantly less than did the control cells. Chemokinetic migration in casein was likewise significantly impaired. As determined by agarose assay, random locomotion of the patient neutrophils was significantly depressed. The differences in phagocytosis and bactericidal activity between the patients and the control subjects were not significant. However, phagocytosis by neutrophils obtained from healthy subjects was significantly impaired in sera from four patients, compared with that in control sera. The follow-up study showed the neutrophil migration defect to be constant in repeated tests, whereas infectious episodes diminished in number after the patients reached the age of 3-7 years.

Small intestinal absorption of amino acids and a dipeptide in pancreatic insufficiency

In this study a perfusion technique has been used to investigate in vivo jejunal absorption and transmural potential difference evoked by the neutral amino acids phenylalanine (56 or 20 mmol/l) and glycine (20 mmol/l), the dibasic amino acid lysine (56 or 5 mmol/l), and a dipeptide glycyl-l-phenylalanine (20 mmol/l) in 11 children with pancreatic insufficiency due to cystic fibrosis and in three children with other causes of exocrine pancreatic insufficiency. Net absorption and potential difference evoked by phenylalanine in both cystic fibrosis and pancreatic insufficiency, and net absorption of glycine in cystic fibrosis were significantly reduced; but the absorption of lysine and glycyl-l-phenylalanine was normal. Absorption of the constituent amino acids from the dipeptide was normal or increased in cystic fibrosis. Thus, these studies show a defect in active absorption of neutral amino acids in cystic fibrosis with pancreatic insufficiency and exocrine pancreatic insufficiency. We speculate that pancreatic factors participate in neutral amino acid absorption.

Unusual surface distribution of concanavalin A reflects a cytoskeletal defect in neutrophils in Shwachman's syndrome

Schwachman's syndrome is characterised by pancreatic insufficiency and frequent infections. Absolute polymorphonuclear leucocyte (PMN) counts are low in many patients, and the PMN show abnormal chemotaxis. It was postulated that a cytoskeletal defect might underlie these abnormalities, and a cytoskeleton-dependent function, the surface distribution and mobility of concanavalin-A receptors, was studied on neutrophils from Schwachman's syndrome patients. Approximately a third of the neutrophils in each patient showed a patched distribution of fluorescein-conjugated concanavalin A (FITC-con A) rather than the usual diffuse staining pattern. These patched neutrophils also bound larger amounts of FITC-con A than diffusely stained or capped PMN from the same patient. Antitubulin treatment did not alter the proportion of patched PMN. These findings suggest that a cytoskeletal defect underlies the patching of FITC-con A on the PMN surface. This defect could also contribute to the abnormal chemotaxis and frequent infections found in Shwachman's syndrome patients.

Late presentation of Shwachman's syndrome

Shwachman's syndrome is a rare cause of pancreatic exocrine insufficiency in childhood. It is usually associated with poor growth, neutropaenia and dyschondroplasia of bone metaphyses. Numerous associated congenital abnormalities and hereditary conditions have been described. The vast majority of cases are diagnosed before the age of two. The case described is of a girl presenting with steatorrhoea at age fourteen. Although of small stature, she had been completely well until that time. While survival of infantile cases into adolescence is reported, presentation of the condition in later years is rare and Shwachman's syndrome should therefore be considered as a possible cause of pancreatic insufficiency in older children and adolescents.

Isolated co-lipase deficiency in two brothers

Two normally developed Assyrian brothers with isolated pancreatic co-lipase deficiency are described. They presented at the age of 5-6 years with loose stools. They had steatorrhoea, and analysis of exocrine pancreatic enzymes in the small intestine showed co-lipase deficiency, while amylase, chymotrypsin, trypsin and lipase were normal. Intraduodenal infusion of purified co-lipase improved fat digestion measured by the triolein breath test. Their steatorrhoea diminished on treatment with enteric-coated pancreatic enzymes.