genetics-16bbbbbbhhbbbjjjjjjjjffggg11-.ppt

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1. Pediatric Pediatric
diseasesdiseases
BY
DR MARYAM WAQAR

2. Causes of congenital anomalies Causes of congenital anomalies
in humansin humans
Genetic causes
Environmental causes
Multifactorial

4. Fetal hydropsFetal hydrops
Fetal hydrops refers to fetal edema fluid
collection during intrauterine growth
Accumulation can be variable, ranging from
severe and generalized (hydrops fetalis,
usually lethal), to more localized, non-lethal
forms, for example, isolated pleural and
peritoneal effusions, or postnuchal fluid
accumulations (cystic hygroma).

5. TYPES
Immune hydrops
Non immune hydrops

7. Immune Hydrops (hydrops fetalis)
Immune hydrops is a hemolytic disorder
caused by blood group incompatibility
between mother and fetus.
If fetal erythrocytes express paternal antigens
that are foreign to the mother, those will elicit
antibody responses that can cause red cell
hemolysis.
 The most important molecules are the Rh D
antigen and ABO blood group antigens.

9. Inborn Errors of Metabolism and Inborn Errors of Metabolism and
OtherOther
Genetic DisordersGenetic Disorders

10. PhenylketonuriaPhenylketonuria
Phenylketonuria (PKU) is an autosomal
recessive disease caused by mutations of the
gene encoding phenylalanine hydroxylase
(PAH), an enzyme that irreversibly converts
phenylalanine to tyrosine
Affected infants have impaired brain
development and mental retardation
Elevated phenylalanine metabolite in the
urine allows early diagnosis

11. Galactosemia
Intestinal mucosal lactase converts lactose into
glucose and galactose; galactose is then
metabolized to glucose by three additional
enzymes. Enzymatic defects lead to
accumulation of toxic metabolites
(galactosemia). The most common and
clinically significant form is an autosomal
recessive mutation in galactose-1-phosphate
uridyl transferase (GALT).
Infants present with vomiting and diarrhea after
milk ingestion, with failure to thrive. Liver,
eyes, and brain are most severely affected

13. Cystic Fibrosis (Mucoviscidosis)Cystic Fibrosis (Mucoviscidosis)
Cystic fibrosis (CF) is
an autosomal recessive
disorder that affects
epithelial cell ion
transport and causes
abnormal fluid secretion
in exocrine glands, as
well as in respiratory,
gastrointestinal, and
reproductive mucosa.

14. Mutation of CFTRMutation of CFTR
The gene mutated in CF encodes the cystic
fibrosis transmembrane conductance regulator
(CFTR) protein—a chloride channel.
CFTR regulates other ion channels and cellular
processes.
CFTR association with the epithelial sodium
channel (ENaC)
CFTR mediates bicarbonate transport.

15. Tumors and Tumor-Like Lesions Tumors and Tumor-Like Lesions
of Infancyof Infancy
and Childhoodand Childhood
Benign tumors are much more common
than malignant tumors

16. Benign Tumors and Tumor-LikeBenign Tumors and Tumor-Like
LesionsLesions
Heterotopia (also called choristomas)
represents microscopically normal cells or
tissues present in abnormal locations (e.g., a
rest of pancreatic tissue in the wall of the
stomach.

17. Hamartomas are excessive (but focal)
overgrowth of mature cells or tissues native
to the organ or site in which they occur, that
do not recapitulate normal architecture

18. HemangiomasHemangiomas
Hemangiomas (benign
vascular tumors) are the
most common tumors of
infancy, most are
cutaneous, with a
predilection for face and
scalp.
 They may enlarge along
with the growth of the
child but commonly
spontaneously regress

19. Fibrous tumorsFibrous tumors
Fibrous tumors range from sparsely cellular
proliferations (fibromatosis) to richly cellular
lesions indistinguishable from adult
fibrosarcomas.

20. Teratoma Teratoma
A teratoma is a tumor made up of several
different types of tissue , such as hair, muscle,
or bone. They typically form in the ovaries
Teratoma occur in sacrococcygeal region in
congenital lesions
Approximately 75% are benign mature
teratomas, while 12% are malignant and lethal

22. Malignant TumorsMalignant Tumors
The most frequent childhood cancers involve:
Hematopoietic system (e.g., leukemia, some
lymphomas)
CNS (e.g., astrocytoma, medulloblastoma,
ependymoma)
Adrenal medulla (e.g., neuroblastoma)
Retina (e.g., retinoblastoma)
Soft tissue (e.g., rhabdomyosarcoma)
Bone (e.g., Ewing sarcoma, osteogenic sarcoma)
Kidney (e.g., Wilms tumor)

23. Neuroblastic tumorsNeuroblastic tumors
Neuroblastic
tumors arise in the
adrenal medulla or
sympathetic
ganglia.

24. Morphology Morphology
These tumors are
characterized by sheets
of small, round blue
neuroblasts within a
neurofibrillary
background (neuropil)
and characteristic
Homer-Wright
pseudorosettes

25. Wilm’s TumorsWilm’s Tumors
Wilms tumor of the kidney is usually
diagnosed between ages 2 and 5 years
Clinical features: Patients typically present
with large abdomenal masses; hematuria,
pain, hypertension, or bowel obstruction is
common

27. Morphology Morphology
Wilms tumors are
soft, large, well-
circumscribed renal
masses characterized
by triphasic histologic
features:
(1) immature stroma,
(2)blastema, and
 (3) tubules—an
attempt to
recapitulate
nephrogenesis.

28. THANK YOUTHANK YOU