الفهرس 
Estimation of body fatnessOnly 14 pages are availabe for public view
 |  | from | 352 |  |  |
| | | from | 352 | | |
Abstract
Many approaches have been tried in order to tackle the problem of obesity in children. Recently
concern has focused on childhood obesity among the most difficult problems that confront
pediatrics. The recent increase in the prevalence of obesity, and the co-morbidities associated
with obesity emphasize the urgency with which effective treatment and prevention ust be developed
and implemented in primary care settings.
The aim of the study was :-
1. Aetiological classification of different groups of obesity according to clinical examination
including pedigree analysis, cytogenetic results and anthropometric measurements.
2. To determine the cytogenetic abnormalities associated with obesity specially the microdeletion
syndromes,
3. To determine the frequency of genetic disorders among · different groups of
obesity •
The study included 50 cases complaining of obesity, and referred to the outpatient clinic of the
Human Genetic Department, National Research center, over a period of about 2 years comprised 1.58%
from the total cases referred to the clink. The cases were subjected to the following investigations :-
1. Careful pedigree construction.
2. Full clinical history and clinical examination.
3. Anthropometric measurements.
4. Intelligent Quotient (IQ).
5. chromosomal studies using G-banding and high-resolution banding techniques.
Other investigations were also done when needed’ as hormonal assay (Serum cortisol AM &PM and
dexametha zone suppression test), slit lamp and fundus examination. The 50 cases were classified
according to the clinical diagnoses mode to the following groups.
Exogenous obesity (24 cases, 48%), Laurence Moon Biedl syndrome (9 cases, 18%}, Prader-Willi
syndrome (15 cases, 30%), one case had Down syndrome and finally one case had Fragile- x syndrome.
The mean age of the cases was 8.4 years, the male to female ratio was 1.38 : 1. Parental
consanguinity rate was 58% and positive family history in 18% of the cases.
For the 24 cases with exogenous obesity, cytogenetic results for the cases showed normal karyotype
in all cases except two cases, who showed inversion of X chromosome. Different levels of IQ varying
from borderline (IQ 71 to 85) to intelligent (126 to 140) were found in all cases except two
cases who were mentally retarded. Parental consanguinity
rate was 24%, the highest rate of consanguineous marriages among other aetiological groups.
As a conclusion, an obesity phenotype is a multi factorial trait determined by genetic and
non-genetic factors. Based on our results, it has been suggested that there is significant
association between excess body fat and a locus located in the X chromosome.
For the nine cases of the · Laurence Moon Biedl syndrome, all of them fulfilled the most diagnostic
criteria of the syndrome. Eight cases were considered ·mentally retarded, two of them scored in the
severe handicap range, the other six cases were in the range of moderate to mild mental
retardation equally. Cytogenetic study showed normal chromosomes for all cases except one
case showed del. (6) (q22-ter).
In conclusion, our results point to the possible presence of a locus for retinitis pigmentosa on
chromosome 6 q 22 ter. Therefore, it is preferable that all patients with 6 q deletion in this
region should have ophthalmic examination.
For our studied 15 cases with Prader-Willi syndrome, seven of them had a mental retardation with a
mean IQ score of 68.4. All cases have fulfilled the major and most minor diagnostic criteria.
Chromosomal study showed different forms of chromosome 15 abnormalities in eleven cases. Our
results were similar to those reported in the literature.In conclusion, the cytogenetic findings confirm the result of
assigning the locus of the Prader-Willi syndrome gene on 15 q 11-
13 or involvement of a region other than 15 q 11-13 in gene expression.
The case with Fragile - x syndrome was presented by clinical picture resembling the Prader-Willi
syndrome. He attained a full score IQ of 49. Cytogenetic studies with G-banding and high
resolution techniques showed normal chromosomes, while chromosomal analysis of cells treated with
.methotrexate showed the fragile site at X q 27.3. This result confirmed those reported in the
literature and agreed with the necessity to perform specific fragile -x studies on mentally
retarded patients presenting with a Prader-Willi phenotype but without the P W S specific molecular
abnormalities.
For the studied case with Down syndrome, the main complaint was obesity and mental retardation.
Clinical examination showed the characteristic phenotype reported in the literature. Cytogenetic
analysis confirmed the diagnosis by finding the extra chromosome 21 in all studied cells.
Finally, 26 cases (52%) out of our 50 obese cases were diagnosed as genetic syndromes associated
with obesity and mental retardation. Furthermore, high percentage of our mentally retarded cases
(48%), The co-morbidities associated with obesity and the recent increase in the prevalence of
obesity emphasize the urgency of proper diagnosis and management of obesity in infancy and early
childhood.