769

IMPORTANCE OF ROUTINE &agr;-FETOPROTEINESTIMATIONS

SIR,-Recent correspondents have reported antenatal mis-Jtagnoses of neural-tube defects’ 2 by x-fetoprotein (A.F.P.)level, the importance of correct technical procedures in makingthese esnmates,3 and alternative interpretations of elevatedt.E.r, values.4 We should like to emphasise the importance ofcarrying out A.F.P. tests as a matter of routine on all specimensof ammotic fluid taken early in pregnancy, for whatever rea-son. We have lately had two excellent examples of the necessityof this.Case .—A 24-year-old patient who was a known carrier for

Duchenne muscular dystrophy had an amniocentests at the 15th weekof pregnancy for sexmg of the fetus, with a view to subsequent ter-

mmation of the pregnancy if the fetus proved to be male. As a matterof routine, the .F.p. level in the amniotic fluid was also determined,using the ’M-Partigen’ plate method, and was found to be 182 ug/ml.The pregnancy was terminated immediately, resulting in a male fetusMtth a large lumbar meningomyelocele. ’

Case 2.-A 44-year-old patient had an ammocentesis at the 17thweek of pregnancy for screening for a chromosome defect. Agam, rou-tmelv the a.r P. level was determined and found to be 82 :Jg/ml,---notso high as in case 1 but still above the normal limits for this labora-tory. As in case 1, a sample was forwarded to Dr M. Ferguson-Smithm Glasgow, who kmdly confirmed that the level was elevated. Thepregnancy was terminated, producing a female fetus with a large sac-ral meningomyclocele. The fetus had a crown/rump length of 170 mm,and the leston was 14-5 5 mm long.

These 2 cases have occurred in the last 110 specimens ofamniotic fluid sent for some examination other than A.F.P. esti-mation but in which this has been examined as a matter of rou-tine. In neither instance was there any previous birth of anaffected child to suggest a high risk of central neural-tube.defect. The incidence appears somewhat higher than that

expected from the population figure, even allowing for theslight elevation of such conditions in the offspring of oldermothers, from whom an appreciable proportion of specimensfor antenatal examination come. They certainly indicate theimportance of A.F.P. screening of all amniotic-fluid specimensthat become available, no matter what the primary reason forobtaining them.

Department of Human Genetics,University of Newcastle upon Tyne.Princess Mary Maternity Hospital,Newcastle upon TyneBishop Auckland General Hospital.

E. V. WRIGHT

A. S. MCINTOSH

J. W. FOULDS

DEFECTIVE ESSENTIAL-FATTY-ACIDMETABOLISM IN CYSTIC FIBROSIS

S)R,—Mr Rivers and Mr Hassam (Oct. 4, p. 642) proposethat the subnormal levels of linoleic acid (18:2) found in theplasma-phospholipids of patients with cystic fibrosis are due tomalabsorption. They also suggest that such patients fail to

show the increase in 5,8,11-eicosatrienoic acid (20:3(.j9) whichis characteristic of dietary E.F.A. deficiency, although the evi-dence they quote seems remarkably scanty, and they hypothe-sise that this is due to the coexistence of a defect in the desatu-ration of 18:2 to arachidonic acid (20:4) and of oleic acid

18:1) to 20:39. To substantiate their hypothesis they deducethat the remarkable remission observed in a cystic-fibrosis pa-uent given intravenous ’Intralipid" was due not to the 18:2content of the 20% triglyceride component of the fat emulsionbut to the 20:4 content of its 1.2% phospholipid componentnot 6[( as they state). This explanation seems unlikely in viewof the relatively small proportion of 20:4 in intralipid phospho-

1. Campbell, S., Pryse-Davies, J., Coltart, T. M., Seller, M. J., Singer, J. D.Lancet 1975, i, 1065.

2. Field B., Kerr, C. ibid. 1975, ii, 324.3. Brock, D. J. H. ibid. p. 495.4. Weinberg, A. G., Milunsky, A., Harrod, M J. ibid p 4965. Elliott. R B, Robinson, P. G Archs Dis. Childh. 1975, 50, 76.

lipid, especially since intravenous administration of intralipidphospholipid to healthy subjects decreases both the 18:2 and20:4 content of their plasma-phospholipids (unpublished data).Comparison of the effects of complete intralipid versus intrali-pid phospholipid on the level of 20:4 in the plasma-phospho-lipids of patients with cystic fibrosis would soon determinewhether they lack the ability to desaturate 18:2 to 20:4, asclaimed by Mr Rivers and Mr Hassam.Medical Research Council LipidMetabolism Unit,Hammersmith Hospital,London W12 OHS. GILBERT THOMPSON

EXACERBATION OF ACRODERMATITISENTEROPATHICA BY SOYA-BEAN MILK FEEDING

SIR,-We read with interest the report of zinc deficiency oc-curring during intravenous alimentation (Sept. 27, p. 605).This has prompted us to describe an infant, under our care in1973, in whom the clinical features of acrodermatitis entero-pathica (A.E.) appeared to be exacerbated by soya-bean milkfeeding.The infant (birth-weight 3.6 kg) developed bilious vomiting and

diarrhcea at 5 weeks of age. Laparotomy was necessary because of in-creasing abdominal distension, but no anatomical obstruction wasfound; a presumptive diagnosis of severe gastroenteritis was consid-ered likely. Postoperatively, adequate nutrition proved difficultbecause of sugar intolerance. Despite a combination of intravenousfeeding and "milk" composed of blended steak, medium-chain fat, andglucose, weight loss continued z 15 kg). He showed a lack of interestin feeding and in his surroundings. Within 3 weeks of operation mildperioral excoriation was noted which did not alter during the next fewweeks. However, within one week of synthetic milk containing soya-bean protein being added to the diet, the severity and extent of therash changed considerably; it became more angry, eczematous, and

weeping, and deep fissures appeared over the chin radiating out fromthe lower lip, but this was confined to the face. The infant was pro-foundly listless and continued to lose weight (3-05 kg).

Although soya-milk feeds were immediately stopped, healing beganonly when the steak mixture was replaced by an aminoacid hydroly-sate of bovine plasma-proteins. This was a fortuitous choice of dietsince it was fortified with 5 mg/100 g of zinc sulphate; for good mea-sure 8 g daily of a mineral mixture was also added to this regimen.This supplied a further 0.9 mg of elemental zinc. Within 3 weeks theperioral rash had largely healed and rapid weight gain had taken place(0-16 kg/week). A normal diet without zinc supplements was intro-duced 4 months later. He subsequently made a complete recovery andremains in excellent health 2 years later.

The importance of zinc_both in the aetiology and treatmentof A.E. is now well established.1 2 It seems highly probable thathad the plasma-zinc been measured at the height of the rash,profound deficiency would have been uncovered. This is par-ticularly likely since the classical exanthem of A.E. onlyappeared following the introduction of feeding with soya-beanmilk. Nutritional studies in rats have shown that this proteinimpairs zinc absorption3 and that in animals on a soya-beandiet normal growth can only be maintained or restored whenzinc supplements are given.4 Although not the sole factor inthe development of A.E. in our patient, we feel that this caseillustrates the hazard of soya-bean milk in the nutritionallydeprived infant.

Finally, in view of the continued good health of our patient,one might ask whether A.E. is a specific disease entity or merelya clinical syndrome related to a disturbance of zinc metabolismwhich may have many causes.

Departments of Child Health and Medicine,Queen’s University of Belfast,Institute of Clinical Science,Grosvenor Road,Belfast BT12 6BJ.

JOHN F. T. GLASGOWMARGARET E. ELMES

1. Moynahan, E. J., Barnes, P. M. Lancet. 1973, i, 676.2. Barnes, P. M., Moynahan, E. J. Proc. R. Soc. Med. 1973, 66, 3273. O’Dell, B. L., Savage, J. E. Proc. Soc. exp. Biol. Med. 1960, 103, 3044. Prasad, A. S., Oberleas, D., Wolf, P., Horowitz, J. P. J clin Invest. 1967,

46, 549.