7/22/2019 1376B

1/5

Phosphoglucomutase Genetic Polymorphismand Body Mass

FULVIA GLORIA-BOTTINI, MD; ANDREA MAGRINI, MD; ELENA ANTONACCI, MD;MAURO LA TORRE, MD; LAURA DI RENZO, MD; ANTONINO DE LORENZO, MD;ANTONIO BERGAMASCHI, MD; EGIDIO BOTTINI, MD

ABSTRACT:Background:We have searched for a pos-sible association of the genetic polymorphism of Phos-phoglucomutase locus 1 (PGM1), a key enzyme in car-bohydrate metabolism, with body mass. Methods:Adults (n 257) with type 2 diabetes, 74 childrenreferred for obesity, and 740 consecutive healthy new-born infants were studied. Body mass index, bodyweight, birth weight, and PGM1phenotype were deter-mined. Sexes were analyzed separately.Results:In type2 diabetes, females carrying the PGM1*2 allele are lessrepresented among subjects with extreme body massindex deviation as compared with other classes of sub-

jects. Among children referred for obesity, femalescarrying the PGM1*2 allele are less represented amongchildren with extreme body weight deviation. Amongconsecutive infants, in both sexes the proportion of

those showing a birth weight higher than the 3rd quartileis lower in homozygous PGM

12/2 subjects than in other

PGM1 phenotypes. Conclusions:The data suggest thatduring extrauterine life, females carrying the PGM1*2allele are relatively protected from extreme body massincrease. During intrauterine life, PGM12/2 homozy-gotes show a tendency to low body mass increase.Because PGM1enzymatic activity depends on its phos-phorylation status by the kinase Pak1, both structuraldifferences of the PGM1 allelic product and differentrates of activation by Pak between sexes might be respon-sible for the pattern observed. At present, the effect of othergenes near PGM1 and in linkage disequilibrium with itcannot be ruled out.KEY INDEXING TERMS:PGM1; Ge-netic polymorphism; Body mass index; Birth weight; Over-weight. [Am J Med Sci 2007;334(6):421425.]

Obesity is a heterogeneous group of disordershaving in common energy balance disturbances

and fat cell increase. Besides excess caloric intakeand a sedentary lifestyle, genetic factors are also ofimportance in the development of obesity. Moreover

variation in energy intake and participation in phys-ical activity are not independent from genetic fac-tors1,2. At present, more than 400 chromosomal re-gions have been identified as candidate genes.37

Moreover, obesity shows different patterns in malesand females, suggesting that sex hormones maymodify the effect of genes involved in the develop-ment of obesity disorders.

Phosphoglucomutase (PGM) is a highly polymor-phic enzyme that plays a key role in glycide metab-olism. Associations with birth weight have been ob-served both in normal and diabetic pregnancy,8,9

suggesting that its genetic variability may be impor-tant for body mass development. Differences be-tween males and females concerning the effect ofPGM1 on birth weight have been also reported.

10

Phosphoglucomutase Polymorphism

Phosphoglucomutase is an enzyme widely distrib-uted in nature that catalyzes the reversible reaction:glucose-1-phosphate glucose-6-phosphate, an

essential step in carbohydrate metabolism. Four sep-arate loci determine distinct sets of PGM isozymes:PGM1, PGM2, PGM3, and PGM4.

1114 About 85% to95% of total PGM activity is determined by the PGM1locus, that shows an electrophoretic polymorphism de-termined by the occurrence of 2 codominant alleles:PGM1*1 and PGM1*2 at a locus on the short arm ofchromosome No. 1). In vitro the activity associatedwith PGM1*2 is higher than that associated withPGM1*1.

15 Recent studies have shown that Pak1 (p-21activated kinase) binds to, phosphorylates, and en-hances the enzymatic activity of PGM1.

16 Differencesin activation between the 2 allelic products of PGM1

From the Department of Biopathology and Imaging Diagnostics(FG-B, AM, EB) and the Department of Neurosciences (LDR, ADL),University of Rome Tor Vergata, School of Medicine, Rome, Italy;the Center of Diabetology (EA) and the Department of Pediatrics(MLT), S. Massimo Hospital, Penne, Italy; and the Institute ofOccupational Health Medicine (AB), Catholic University of Holy

Hearth, Rome, Italy.Submitted February 16, 2007; accepted in revised form April 11,

2007.Correspondence: Dr. Fulvia Gloria-Bottini, Department of Bio-

pathology and Imaging Diagnostics, University of Rome, TorVergata, Via Montpellier, 1, 00133 Rome, Italy (E-mail: gloria@med.uniroma2.it).

421THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES

7/22/2019 1376B

2/5

are likely but have not yet been investigated. Thus,in vivo, differences in enzymatic activity betweenPGM1 phenotypes could be more marked relative tothose observedin vitro.

Isoelectrofocusing1719 and heat denaturation20

studies have revealed a greater variability within

the PGM1 locus leading to the identification of 8different PGM1 alleles. Recent evidence indicatesthat intragenic recombination has an important rolein generating PGM1 variability.

2125

The central role in glycide metabolism, the organ spec-ificity of some sets of PGM isozymes (the PGM4 locus isactive only during lactation and its isozymes arepresent only in milk14), the variable proportion of dif-ferent sets of isozymes between different tissues andwithin a given tissue,13 and the presence of genetic poly-morphism in all human populations strongly suggestthat genetic variability of PGM is adapted to specificfunctions of tissue and organs and may have impor-tance in energy expenditure and physical activity.

In the present study, we searched for a possible asso-ciation of the PGM1 phenotype with body mass in adultsand children and with birth weight in newborns fromnormal pregnancy. Sexes have been analyzed separately.

Materials and Methods

Samples Studied

Adults With Type 2 Diabetes. Adults (n 257) with type 2diabetes from the Caucasian population of Penne, a small ruraltown in southeastern Italy, were studied. The sample was chosenrandomly from a population of about 2000 subjects under care at theCenter of Diabetology of the local hospital. Samples were collectedover a period of about 18 months from patients scheduled for met-

abolic control on a previously fixed day of the week. The sampleincludes male and female patients (mean age, 66.3 years; SD, 9.8).

Children Referred for Obesity. Caucasian children (n 74; ages between 3 and 14 years), referred for obesity to theout-patient Department of our Pediatric Clinic, were studied.Children were considered obese if their weight exceeded morethan 20% the mean weight for their age, height, and sex. Allchildren were above median height. The cutoff point betweenmoderate and severe deviations of body mass was fixed on 4standard deviations above the mean. Cases considered for our

analysis were not associated with known disease and did notshow abnormalities of the following parameters: glycemia, tri-glyceridemia, cholesterolemia, and urinalysis with determinationof free cortisol in the urine.

Newborns From Healthy Women. Consecutive healthy new-born infants (n 740) collected from the Caucasian populationsof Rome and Penne were studied. No significant differences inPGM1 distribution, birth weight, and gestational age were ob-served between the sample of Rome and that of Penne. Birthweight percentile was evaluated for each class of gestational ageaccording to tables for the population of Florence.25 Gestationallength was estimated from the date of the last menstrual periodand checked with Dubowitz score as an additional index of neo-natal maturity.

Blood samples in adults and children were obtained by vasopunc-ture. Newborn blood samples were collected from the placental side

of umbilical cord after its section. The investigation was approved bythe Department of Biopathology and Imaging Diagnostics, and pa-tients or parents of children gave informed consent to be included orinclude their children in this investigation.

Laboratory and Statistical Methods

PGM1 phenotype was determined in all subjects by starch gelelectrophoresis according to the method of Spencer et al.11 The 2

test of independence was performed, using SPSS programs.26

Three-way contingency tables were analyzed, using a log-linearmodel according to Sokal and Rohlf.27 Combined probabilitieswere evaluated according to Sokal and Rohlf.27

Results

Table 1 shows the proportion of subjects withextreme body mass distribution (body mass index

Table 1. Percent Proportion of Subjects With Severe Body Mass in Adults With Type 2 Diabetes and of Children Referred forObesity in Relation to PGM1 Phenotype and Gender

Adult Subjects With Type 2 Diabetes

Males Females

PGM11/1 Phenotype PGM1*2 Carriers PGM11/1 Phenotype PGM1*2 Carriers

Proportion of subjects withBMI 35

9.2% 16.1% 15.5% 6.1%

No. of subjects 65 56 71 65Three-way contingency table analysis by log linear model x PGM1; y BMI; z sex; xyz interactionP 0.045Independence between BMI and gender: in PGM11/1 P 0.300: in carriers of PGM1*2 allele P 0.070

Children Referred for Obesity

Males Females

PGM11/1 Phenotype PGM1*2 Carriers PGM11/1 Phenotype PGM1*2 Carriers

Proportion of children withweight 4 SD

33.3% 27.8% 34.6% 6.7%

N of children 15 18 26 15

Three way contingency table analysis by log linear model x PGM1; y BMI; z sex; xyz interactionP 0.150Independence between BMI and gender: in PGM11/1 P 0.980: in carriers of PGM1*2 allele P 0.024Combining probabilities: for interactionP 0.040; for independence between body mass and gender in carriers of PGM1*2 alleleP 0.013

PGM1 and Body Mass

422 December 2007 Volume 334 Number 6

7/22/2019 1376B

3/5

7/22/2019 1376B

4/5

PGM1 phenotype and gender. In both males and fe-males carrying the homozygous PGM12/2 phenotype,the proportion of those with a birth weight higher thanthe 3rd quartile is much lower than in the other PGM1phenotypes (PGM11/1 and PGM1 1/2).

Discussion

The data suggest that during extrauterine life,females carrying the PGM1*2 allele are relativelyprotected from extreme body mass increase. Duringintrauterine life PGM12/2 subjects of either sexshow a tendency to reduced body mass increase. Theassociation between PGM1and body mass is similarin 3 independent conditions arguing against thepossibility of sampling chance artifact.

Considering the key role of PGM1in glycide metab-olism, we are disposed to consider a causal mechanismfor the statistical associations reported. However, the

effect of other genes near PGM1 and in linkage dis-equilibrium with it cannot be excluded. In addition toPGM1, other genes important in the glycolytic path-way are clustered on the short arm of chromosome 1including glucose dehydrogenase (GDH), 6-phosphoglu-conate dehydrogenase (PGD), UDP-galactose-4-epimer-ase (GALE), and glucose transport 1 (GLUT1).28

PGM1 is located at 1p31, and in the same area isalso located the leptin gene promoter (LEPR), whichhas been implicated in obesity risk.2931 Since PGM1and LEPR are nearly 2 millions of bp apart, a stronglinkage disequilibrium appears unlikely32 but can-not ruled out. Therefore, the possibility of a causalrole of LEPR cannot be excluded.

At present, there is great interest in elucidatingthe molecular mechanisms, especially those con-cerning the signal transduction pathways, involvedin gender differences concerning development andbody composition.33 PGM1and Pak1 seem promisingcandidate genes for studies in this area.

From a practical point of view, the identification offactors involved in metabolism that show a genetic

variability associated to predisposition/resistance toan increase of BMI may have clinical relevance forprevention and cure of obesity disorders.

AcknowledgmentsWe thank Prof. James MacMurray for helpful

advice.

References

1. Webber J. Energy balance in obesity. Proc Nutr Soc 2003;

62:53943.2. Loktionov A. Common gene polymorphisms and nutrition:

emerging links with pathogenesis of multifactorial chronic

diseases (review). J Nutr Biochem 2003;14:42651.3. Speakman JR. Obesity, the integral roles of environment

and genetics. J Nutr 2004;134:2090S105S.

4. Cancello R, Tounian A, Poitou CH, et al. Adiposity sig-

nals, genetic and body weight regulation in humans. Diabetes

Metab 2004;30:21527.5. Tremblay A, Doucet E. Obesity: a disease or a biological

adaptation? Obes Rev 2000;1:2735.6. Ochoa Mdel C, Marti A, Martinez JA. Obesity studies in

candidate genes. Med Clin 2004;122:54251.

7. Snyder EE, Walts B, Perusse L, et al. The human obesitygene map: the 2003 update. Obes Res 2004;12:369439.

8. Bottini E, Gerlini G, Fallucca F, et al. Diabetic pregnancy:

fetal development and maternal phosphoglucomutase pheno-

type. Dis Markers 1985;3:839.9. Gloria-Bottini F, Lucarini N, Bonci E, et al. Genetic

polymorphism and intrauterine development: the role of ma-

ternal PGM1and MNSs genotypes. Am J Dis Child 1986;140:

3246.10. Gloria-Bottini F, Lucarini N, La Torre M, et al. Birth

weight and parental PGM1alleles. Am J Hum Biol 2001;13:

41720.11. Spencer N, Hopkinson DA, Harris H. Phosphoglu-

comutase polymorphism in man. Nature 1964;21:7425.12. Hopkinson DA, Harris H. A third phosphoglucomutase

locus in man. Ann Hum Genet 1968;31:35967.13. McAlpine PJ, Hopkinson DA, Harris H. The relative activ-

ities attributable in three phosphoglucomutase loci (PGM1,

PGM2, PGM3) in human tissues. AnnHum Genet 1970;34:169

75.14. Cantu JN, Ibarra B. Phosphoglucomutase evidence for a new

locus expressed in human milk. Science 1982;216:63940.15. Scacchi R, Corbo RM, Palmarino R, et al.Human phos-

phoglucomutase locus 1: red cell enzymatic activities associ-

ated with common isoelectric focusing phenotypes. Hum

Hered 1983;33:21822.16. Guguraj A, Barnes CJ, Vadlamudi RK, et al. Regulation

of phosphoglucomutase 1 phosphorylation and activity by a

signalling kinase. Oncogene 2004;23:811827.17. Bark JE, Harris MJ, Firth M. Typing of the common

phosphoglucomutase variants using isoelectric focusing- anew interpretation of the phosphoglucomutase system. J Fo-

rensic Sci Soc 1976;16:11520.18. Kuhnl P, Schmidtmann U, Spielmann W. Evidence for

two additional common alleles at the PGM1 locus (phospho-

glucomutase, E.C.2.7.5.1): a comparison by three different

techniques. Hum Genet 1977;35:21923.19. Sutton JG, Burgess R. Genetic evidence for four common

alleles at the phosphoglucomutase 1 locus (PGM1) detectable

by isoelectric focusing. Vox Sang 1978;34:97103.20. Scozzari R, Trippa G, Santachiara-Benerecetti AS, et al.

Further genetic heterogeneity of human red cell phosphoglu-

comutase 1: a nonelectrophoretic polymorphism. Ann Hum

Genet 1981;45:31322.21. Whitehouse DB, Putt W, Lovegrove JU, et al. Phospho-

glucomutase 1: complete human and rabbit mRNA sequencesand direct mapping on this highly polymorphic marker on

human chromosome 1. Proc Natl Acad Sci U S A 1992;89:

4115.22. March RE, Putt W, Hollyoake M, et al. The classical

human phosphoglucomutase (PGM1) isozyme polymorphism

is generated by intragenic recombination. Proc Natl Acad Sci

U S A 1993;90:107303.23. Takahashi N, Neel JV. Intragenic recombination at the

human phosphoglucomutase 1 locus: predictions fulfilled.

Proc Natl Acad Sci U S A 1993;90:107259.24. Yip SP, Lovegrove JU, Rana NA, et al. Mapping recom-

bination hotspots in human phosphoglucomutase (PGM1).

Hum Mol Genet 1999;8:1699706.

PGM1 and Body Mass

424 December 2007 Volume 334 Number 6

7/22/2019 1376B

5/5

25. Panero C, Romano S, Cianciulli D, et al. Auxometric

parameters and gestational age in 9751 newborns in Flo-

rence. J Foet Med 1983;3:95103.26. SPSS/PC Version 5.0. Chicago, SPSS Inc, 1992.27. Sokal RR, Rohlf FJ. Biometry. New York, Freeman,

1981.28. McKusick VA. Mendelian inheritance in man. 11th edition.

Baltimore, MD, Johns Hopkins University Press, 1994.29. Portoles O, Sorli JV, Frances F, et al. Effect of genetic

variation in the leptin gene p romoter and the leptin receptor

gene in obesity risk in a population-based case-control study

in Spain. Eur J Epidemiol 2006;21:60512.

30. Park KS, Shin HD, Park BL, et al. Polymorphisms in the

leptin receptor (LEPR): putative association with obesity and

T2DM. J Hum Genet 2006;51:8591.31. Duarte SF, Francischetti EA, Genelhu-Abreu V, et al.

p.Q223R leptin receptor polymorphism associated with obe-

sity in Brazilian multiethnic subjects. Am J Hum Biol 2006;

18:44853.

32. Dawson E, Abecasis GR, Bumpstead S, et al. A first-generation linkage disequilibrium map of human chromo-

some 22. Nature 2002;418:5448.33. Whitacre CC, Reingold SC, OLooney PA. A gender map

in autoimmunity. Science 1999;283:12778.

Gloria-Bottini et al

425THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES