PIRACICABA UNIV,FAC MED,DEPT PEDIAT,CAMPINAS,BRAZILUNIV São Paulo,FAC MED,DEPT NEUROL,São Paulo,BRAZILWeb of Scienc

Diamet, A. J.

Nishimura, R.

Schmidt, Benjamin Jose

Wakamoto, M.

Pediatric Research

B J Schmidt

A J Diamet

R Nishimura

M Wakamoto

Crossref

Tay-Sachs Disease Heterozygote Selection

The authors determined the serum hexosaminidase A levels in 197 subjects (106 males and 91 females); 174 were adults and 23 were children aged from 20 days to 15 years; 13 of the children were of Jewish origin, the other 10 children were non-Jewish. Of the total 197 subjects, 94 (51 males and 43 females) were Jews whose ancestors lived in Western and Central Europe (Ashkenazi). The other 103 subjects (53 males and 50 females) had no Jewish ancestors.

The serum hexosaminidase A levels were determined following the method of O'Brien et al. (1970) modified by Kaback (Methods Enzymol., 28: 862 (1973)). In those cases where the results were doubtful, especially in the pregnant women (6), the hexosaminidase A levels were also tested in the leukocyte, according to the method described by Kaback and Zeiger (Advan. Exp. Med. Biol., 19: 13 (1972)). The results are presented in Table 1.

Comments: The high incidence of heterozygote carriers of Tay-Sachs disease in Ashkenazi Jews (1:30), emphasized once more by this investigation, justifies the population screening for these heterozygotes, particularly among Jews, in order to offer genetic counseling and try to prevent further cases of Tay-Sachs disease.PIRACICABA UNIV,FAC MED,DEPT PEDIAT,CAMPINAS,BRAZILUNIV São Paulo,FAC MED,DEPT NEUROL,São Paulo,BRAZILUniversidade Federal de São Paulo, EPM, São Paulo, BrazilWeb of Scienc

Schmidt, Benjamin José [UNIFESP]

Repositório Institucional UNIFESP

anomaly has not been proven in man. The detection of position effects might be possible in man by the analysis of apparently balanced translocations and a search for correlations between specific breakpoints and phenotypic abnormalities. A dysmorphic and mentally retarded boy has been found presumably carrying a d e  novo balanced translocation which involves the long arms of chromosomes 13 and 18. Breakpoint mapping the long arms of the chromosomes 13 and 18 has revealed presumptive evidence for a position effect in 18q2 1. Possible Evidence of Y Chromosome in Testicular Tissue of Patients with True Hermaphroditism and Karyotype 46,XX C. BERGADA AND R. COCO Division of Endocrinology, Hospital de Ninos, Buenos Aires, Argentina It is widely accepted that male determinant genes must be present, at least in primordial germinal ce!ls, in order to determine testic- ular differentiation. However, exceptions have been reported, such as the existence of XX in apparently normal males and in the majority of true hermaphrodites. Several theories have been ad- vanced to explain the existence of testicular tissue in the absence of a Y chromosome, but they have not been confirmed cytologi- cally. The present work attempts to detect the presence of a Y chromosome by the quinacrine fluorescence technique in histo- logic sections of gonads from three patients with true hermaphro- ditism and somatic cell karyotypes 46,XX. Typical fluorescence of the Y chromosome was found in the testicular tissue from the three patients, indicating the existence of the Y chromosome in gonadal tissue. These findings strongly support the hypothesis that a Y chromosome is necessary for testicular differentiation. Partial Trisomies and Deletions of Chromosome 13 ROBERTO COCO AND GRACIELA M. DEL REY Laboratory of Cytogenetics, Division of Endocrinology, Hospital de Ninos, Buenos Aires, Argentina With the advent of new banding techniques there have been increasing numbers of patients with trisomies and deletions for specific portions of chromosome 13 discovered. Some authors have suggested a preliminary phenotypic mapping of chromosome 13. We have studied five ~atients with trisomies and deletion of parts of chromosome 13 ;sing banding techniques and we have attempted a karyotype-phenotype correlation. 1) Deletion 13931 + 13qter: karyotype 46,XX,de1(13) (13pter- 13q31:) is associated with mental retardation, craniofacial asymmetry, microcephaly, wide forehead, short philtrum, large mouth with protruding and wide spaced superior incisors, prominent and wide nasal bridge, large ears, hypertelorism, retinoblastoma of left eye, and kypho- scoliosis. 2) Deletion 13q31/13q32/13q33 + 13qter: karyotype 46,XY, 13r is associated with growth and mental retardation, large eyes, epicanthus, hypertelorism, frontal bossing, high arched pal- ate, short philtrum, protruding and wide spaced superior incisors, simple low set ears, hypoplastic fingernails, posterior prominence of heel, deep crease of hallux, dorsiflexed first toe, and a third toe longer than the other toes in both feet. 3) Trisomy 13912--13qter: karyotype 46,X,+t(Y; 13)(ql l:q12)(Ypter + Yql 1: 13q12 + 13qter:) is associated with trigonocephaly, craniostenosis with prominent metopic suture, epicanthus, colobomata of left iris, high arched palate, dysplastic low set ears, postaxial symmetric poly- dactyly, abnormal flexion of fingers, hypoplastic fingernails, and bilateral club feet. 4) Trisomy 13913 + 13qter: karyotype 46,XX,t(5;13)(p14;q13)(13qter + 13q13::5p14 -+ 5qter)pat. is as- sociated with growth retardation, microcephaly, craniostenosis, sloping and prominent forehead, protruding nasal bridge, short palpebral fissures, bilateral cleft lip, cleft palate, short neck, ab- normal flexion of fmgers, simian crease, clinodactyly of fifth fingers, bilateral club feet, and duplication of fifth toe with syn- dactyly in the right foot. 5) Trisomy l3pter + 13912: karyotype 47,XX,+del(13)(13pter + 13q12:) is associated with mental retar- dation, microophthalmy, enophthalmy, colobomata of iris and glaucoma of left eye, bilateral preauricular dimples, imperforate anus, rectovulvar fistual, and double left calyceal system. These observations permitted phenotypic mapping of the partial trisomic and monosomic segments in cases 1, 2, 3, and 5, which was not possible in case 4 because the patient also had a partial monosomy of chromosome 5. The deletions of the short arm of chromosome 13 (case 2) and long arm of chromosome Y (case 3) were considered to have no significant functional effect. Tay-Sachs Disease Heterozygote Selection B. J. SCHMIDT, A. J. DIAMET, R. NISHIMURA, AND M. WAKA- MOT0 Departamentos de Pediarria da Far. Med. Sorocaba-PUC-Sao Paulo e Neurologia da EM.  U.S.P., Sao Paulo, Brazil The authors determined the serum hexosaminidase A levels in 197 subjects (106 males and 91 females); 174 were adults and 23 were children aged from 20 days to 15 years; 13 of the children were of Jewish origin, the other 10 children were non-Jewish. Of the total 197 subjects, 94 (51 males and 43 females) were Jews whose ancestors lived in Western and Central Europe (Ashkenazi). The other 103 subjects (53 males and 50 females) had no Jewish ancestors. The serum hexosaminidase A levels were determined following the method of O'Brien et al. (1970) modified by Kaback (Methods Enzymol., 28: 862 (1973)). In those cases where the results were doubtful, especially in the pregnant women (6), the hexosamini- dase A levels were also tested in the leukocyte, according to the method described by Kaback and Zeiger (Advan. Exp. Med. Biol., 19: 13 (1972)). The results are presented in Table 1. Table 1. S e r u m  hexosaminidase A in Jews a n d  non-Jews - Hexosaminidase Children (23) Adults (174)' A serum (% A of total) Jewish Non-Jewish Jewish Non-Jewish (13) (10) (81) (93) >40% (normal 9 8 57 83 homozygotes) 30-40% ("doubt- 5 1 14 9 ful" cases) <30% (heterozy- 0 1 10 1 gotes) ' In the pregnant women in which results from 15.6-35.0% of serum hexosaminidase A were found, the leukocyte tests showed levels within the limits of normal homozygotes. Comments: The high incidence of heterozygote carriers of Tay- Sachs disease in Ashkenazi Jews (1:30), emphasized once more by this investigation, justifies the population screening for these heterozygotes, particularly among Jews, in order to offer genetic counseling and try to prevent further cases of Tay-Sachs disease. Anti-Human Growth Hormone (HGH) Antibody Determi- nation in HGH-treated Patients M. FAHRER, J. HEINRICH, M. RIVAROLA, AND C. BER- GADA Division of Endocrinology, Hospital de Ninos, Buenos Aires, Ar- gentina Determinations of anti-HGH antibody were performed by ra- dioimmunoassay in 57 patients with pituitary insufficiency who had been treated with human growth hormone (HGH). Antibodies were not detected in 38 patients, 10 had low antibody titers (1:lS-1:120), 4 medium titers (1:120-1:960), and 5 high titers (of 1:960). In 42 patients, antibody titers could be correlated with growth velocity during HGH treatment. An adequate growth velocity was observed in 25 of 27 patients with negative titers, 5 of 7 with low titers, 3 of 4 with medium titers, and 1 of 4 with high 

Tay-sachs disease heterozygote selection

TAY-SACHS DISEASE HETEROZYGOTE SELECTION

TAY-SACHS DISEASE HETEROZYGOTE SELECTION

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