Familial neurovisceral lipidosis

152

Letters to the editor

evaluation of the effects of corrective cardiac operation on intellectual and emotional development. We take issue with his statement that "I.Q. cannot be determined until the child is mature enough to take an intelligence test," which Dr. Whitaker implies is at age 3 years. We administered the Cattelt Infant Intelligence Scale which is a downward extension to age 6 months of the Stanford-Binet Scale. Several other remarks in his tetter deserve comment. We were unable to find any documentation of his statement that " . . . at least two thirds of the I.Q. is determined by genetic factors." We would agree that an interaction occurs between genetic and environmental factors. In our data, mean I.Q. of normal siblings of patients with cardiac disease was closer to the mean I.Q. of a group of unrelated normal children than to that of their siblings with cardiac disease. In another analysis, there was an absence of the expected correlation between I.Q. of the cyanotic children and the educational level of the father, a relationship which existed in all other groups. We agree with Erlenmeyer-Kimling and Jarvik that the "intellectual level is not unalterably fixed by the genetic constitution. Rather, its expression in the phenotype results from the patterns laid down by the genotype under given environmental conditions." We feel that our data further indicate the profound influence on I.Q. of the individual's internal and external environment. LEONARD M. LINDE, M.D. DEPARTMENT

OF

PEDIATRICS, DIVISION

OF CARDIOLOGY BEATRICE RASOF~ M.A. D E P A R T M E N T OF PSYCHOLOGY OLIVE j . D U N N , PH.D. D E P A R T M E N T OF PUBLIC H E A L T H AND PREVENTIVE MEDICINE UNIVERSITY OF CALIFORNIA

The Journal o[ Pediatrics July 1968

histochemical stains which in my view could well be interpreted to a different end. The storage substance(s) which they appear to have preserved adequately by freeze drying and formaldehyde vapor fixation was PAS positive, took up alcian blue (no pH mentioned), and was positive with aldehyde fuchsin. These reactions show the presence of an acidic group and sugar residues. The acidic group was not sufficiently strong to exhibit alcohol stable metachromasia with toluidine blue. These reactions are insufficient to claim the presence of acidic mucopolysaccharide. There are at least two other substances which would give the above reactions. Cerebroside sulfate gives the reactions stated, but this should have been preserved in the frozen sections of glutaraldehyde fixed tissue. The other substance which would give these reactions is a gang]ioside containing sialic acid, a substance which has been reported to be present in excess in this disease by at least two groups of workers (O'Brien and associates: Am. J. Dis. Child. 109: 338, 1965; Sacrez and associates: Pddiatrie 22: 143, 1967). If the authors wish to prove their assumption of acidic mucopolysaccharide accumulation and to exclude the storage of ganglioside, then several more stains are necessary. I would suggest that Sudan black, high iron diamine, alcian blue alone and in the presence of various concentrations of salts and various pH values, a Bial reaction for sialic acid and methylene blue extinction to indicate the nature of the acidic group, are some which should be done. A Bracco-Curti reaction for sulfate is also indicated. In conclusion, the authors have not proved the presence of acidic mucopolysaccharide, neither have they disproved the accumulation of ganglioside by their short series of histochemical reactions. Before proposing the accumulation of two major substances in one disease, further investigation is required.

LOS A N G E L E S , CALIF.

B. D. LAKE~ PH.D. L E C T U R E R IN

I{ISTOCHEMISTRY

D E P A R T M E N T OF MORBID

Familial neurovisceral lipidos6"

ANATOMY T H E HOSPITAL FOR SICK

CHILDREN~

To the Editor: I write to draw attention to conclusions reached by Drs. Scott, Lagunoff and Trump in their article "Familial neurovisceral lipidosis" (J. PEDIAT. 71: 357, 1967). The conclusions were based on their interpretation of a short series of

LONDON, ENGLAND

Reply To the Editor: Dr. Lake has questioned the identification of the storage substance in the visceral epithelial