Genetic Disorders: Experience in Saudi Arabia
Jumana Y. Al-Aama, Alaa Y.Edrees
Princess Al Jawhara Center of Excellence in the Research of Hereditary Disorders,
King Abdul-Aziz University, Jeddah, Saudi Arabia
ABSTRACT
InThe Medical Genetic Unit of King Abdulaziz University in Jeddah was established
by the author in February 2005. It contains the first genetic clinics in the Western
region of the Kingdom of Saudi Arabia. Jeddah, the commercial capital and the
second largest city of Saudi Arabia, has a population of over 3.5 million people with
a 2.06% growth rate and the median age of 21.4 years. Referrals are received from
Jeddah and surrounding cities and towns in the Western Region including among
others Makkah, Taif, and Al-Baha. The objectives of this prospective study were to
study the pattern of genetic disorders over a 4 year period, elucidate their inheritance
patterns, set up a platform for a genetic database in the region and identify the
relevant risk factors for genetic conditions in our population, especially those which
are potentially preventable. Nine hundred and four patients with genetic disease
have been assessed. Each patient received a full genetic assessment including s
dysmorphological examination. Imaging and laboratory testing (including genetic
testing) were done as appropriate. The most likely inheritance pattern was based on
the diagnosis and analysis of family pedigree. The most common form of genetic
disease was autosomal recessive followed by chromosomal disorders and then
autosomal dominant disorders. Unlike some other reports from Saudi Arabia,
consanguinity was more likely to be present in individuals with autosomal recessive
disorders than with any other form of genetic disease including isolated congenital
malformations. Recommendations to decrease the burden of genetic disease in this
region including our experience with the current Premarital Screening in our student
population are discussed.
Distribution of Underlying Etiology
The Most Common Autosomal Recessive Disorders
Cerebellar Dygenesis
Neimann-Pick Disease
CDP
Neurodegenerative disease
Cockayne syndrome
O. I. type 3
Collodion baby
O. I.
Congenital Adrenal hyperplasia
PKU
Congenital myopathy
Retinitis pigmentosa
Congenital nephrotic syndrome
RCDP type 1
Sonada-Kaouna
Russel Silver syndrome
Dubowitz syndrome
Sanjad-Sakati syndrome
JEB
SCA
Ehlers-Danlos syndrome,
Seckel syndrome
type VI
SMA
Familial hypermagnesemia
Spinocerebellar Ataxia
60
GSD type III
Tay-Sach Disease
50
Hurler syndrome
Walker-Warburg syndrome
Jarcho-levin syndrome
Wolcott-Rallison syndrome
Joubert syndrome
Xeroderma pigmentosa
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Types of Chromosomal Disorders
70
40
30
20
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BACKGROUND
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Comparison of advanced maternal age between individuals with
trisomies vs. all other groups :
Trisomies: 60% of mothers were of AMA.
Others: 27.6% of mothers were of AMA.
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Population of Saudi Arabia is a mixture of ethnic groups
Specific genetics and cultural factors
Consanguinity rates: 2560%Diminished awareness of the importance of genetic counseling in preventing
malformations
0
Most common Autosomal Dominant Disorders
JEDDAH
OBJECTIVES
Study the pattern of genetic disorders at the western region of KSA over a 24 month period
Elucidate the inheritance patterns for these genetic disorders
Determine the relevant risk factors for genetic conditions in this population- especially
those that are potentially preventable
Provide recommendations for reduction of genetic disorders- role of genetic counseling
and feasibility of antenatal diagnosis
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CONSANGUINITY
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Cosmopolitan city
Population >3 million
Commercial capital of Saudi Arabia
Western coast of the Red Sea
Multicultural society
Heterogeneous population
35
30
25
20
15
10
5
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Unlike some other reports from Saudi Arabia, consanguinity was more
likely to be present in individuals with autosomal recessive disorders
(56.25% ) than with any other form of genetic disease ( 22.9%)including
isolated congenital malformations
In 38.8% of infants with congenital malformations the parents were
consanguineous.
CONCLUSIONS:
X-linkd Disorders
Diagnosis
No.
DMD
2
Fragile X
X-linked hydrocephalus
Aicardi syndrome
Simpsom-Golabi-Behmel syndrome
Lesch Nyhan syndrome
Retinitis pigmentosa (x-linked type)
orotic aciduria
X-linked Thalassemia with mental retardation
Rett syndrome
Oro-facial digital syndrome (OFD) type II
3
3
3
2
9
14
1
1
1
1
Estimated recurrence risk of genetic disorders is > 1% in almost all cases
and more than half RR ≥ 25%.
Overall 32.61% of all cases had a RR >1% AND Antenatal diagnosis was
possible and feasible
The need for genetic counseling is underscored by the fact that 55.4% of
mothers were <36 years and likely to have further children.
Factors amenable to premarital and preconception counseling and more
common in the region are consanguinity and advanced maternal age.
A condensed public education program in addition to education of all
health care providers who can play an essential role will be highly cost
effective in reducing the burden in genetic disorders in the KSA.