down syndrome and klinefelters syndrome
TRANSCRIPT
TRISOMY 21- DOWN SYNDROMEAND
KLINEFELTER’S SYNDROME
By : SEJWAL MADHUR KUMAR
CONTENTS 1.DOWN SYNDROME 2.KLINEFELTER
SYNDROME INCIDENCE
GENETICS
CLINICAL FEATURES
HEMATOLOGICAL DISORDERS
DIAGNOSIS
MORTALITY
• CAUSES • CLINICAL FEATURES• COMPLICATIONS• INVESTIGATIONS
DOWN SYNDROME
INCIDENCEIf maternal age is <20 yrs ,Approximately 1 in 1550 live births, But if maternal age is >45 yrs ,incidence is 1 in 25 live births
Most common
chromosomal disorder
Genetics
Trisomy 21 (47,XX, +21), - 94 %, The frequency of trisomy increases with increasing maternal age.
Robertsonian translocation involving chromosome 21- Approx. 3-4 %, not related to maternal age.
Trisomy 21 mosaicism – 1-2% cases
Clinical Features
Head and neck Flat facial profile
Up-slanting palpebral fissures
Epicanthal folds
Brushfield spots
Flat nasal bridge
Folded or dysplastic ears
Open mouth
Protruding tongue
Short neck
Excessive skin at the nape of neck
Extremities Short broad hands
Short fifth finger
Incurved fifth finger
Transverse palmer crease
Space between first and second toe
Hyper flexibility of joints
Mental Retardation
Almost all DS babies have MR.
Mildly to moderately retarded .
Starts in the first year of life.
Average age of sitting(11 mon), and walking (26 mon) is twice the typical age.
First words at 18 months.
IQ declines through the first 10 years of age, reaching a plateau in adolescence that continues into adulthood.
Heart DiseaseGI Abnormalities 50 % of Down Syndrome pts have heart disease
Atrioventricular septal defect
VSD
Secundum ASD
Mitral valve prolapse
Valvular malformation
GI abnormalities –in 5% cases of DS
Duodenal atresia or stenosis
Oesophageal atresia and intestinal stenosis
Hematologic disorders
The risk of leukemia is 1 to 1.5 percent.
65% of newborn have polycythemia resulting in hypoglycemia.
Risk of AML ( ACUTE MEGAKARYOBLASTIC LUEKEMIA )is also much higher than the general population.
Transient leukemia.
Diagnosis
Prenatal screening
If no screening – It is recognized from the characteristic phenotypic features.
Confirmed by Karyotype.
MortalityMedian age of death has increased from 25 yrs
to 49 yrs , an average of 1.7 yrs increase per
year.
Most likely cause of death is CHD, Dementia,
Hypothyroidism and Leukemia.
Improved survival is because of increased
placements of infants in homes and
changes in treatment for common causes of
death.
Survival is better for males and blacks.
KLINEFELTER’S SYNDROME
KLINEFELTER SYNDROME
It is the state of male hypogonadismdue to 2 or more X chromosome with 1 or more y chromosome.
INCIDENCE : 1 in 2000 live male births
KARYOTYPE: 82% have classical 47,XXY
15% mosaics , 46XY/47,XXY
Remaining polysomic individuals
cause
MEIOSIS 1
(GAMETOGENESIS)
NON DISJUNCTION
occurs when
homologous
chromosomes ( X and Y)
fails to separate and
producing a sperm with
extra X and Y
chromosome
Clinical features
Abnormally increased distance between pubic ramus and sole of feet.
Lower body appears abnormally elongated also called as EUNUCHOID BODY HABITUS
CLINICAL FEATURES
Atrophied testes - testicular biopsy shows atrophied hyalinised seminiferous tubules with no spermatogenesis.
Lack of secondary sexual characteristics
Gynecomastia is seen
Mental intelligence is near normal
Greater the number of X chromosome ,lower is the level of intelligence
COMPLICATIONS
Infertility
20x increased risk of ca breast
Increased risk of germ cell tumor
Increased risk of autoimmune diseases like SLE (SYSTEMIC LUPUS ERYTHEMATOSUS)
INVESTIGATION
Plasma gonadotropin level
Testicular biopsy
Total sperm count
karyotyping
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