diseases Flashcards
(18 cards)
Cause: Failure of neural tube closure.
Germ Layer: Ectoderm.
Abnormality: Incomplete spinal cord and vertebral arch development.
Molecular Basis: Disruption in folate metabolism; mutations in VANGL2, FZD3.
Physiology: Neurological deficits; paralysis below defect
Spina Bifida
Cause: Neural tube fails to close at cranial end.
Germ Layer: Ectoderm.
Abnormality: Absence of major portions of brain/skull.
Molecular Basis: Folate deficiency; mutations in SHH, MTHFR.
Physiology: Fatal; lack of consciousness, sensory function.
Anencephaly
Cause: Defective neuronal migration.
Germ Layer: Ectoderm.
Abnormality: Smooth brain (no gyri/sulci).
Molecular Basis: Mutations in LIS1, DCX genes.
Physiology: Seizures, developmental delay, early death.
Lissencephaly
Cause: Maldevelopment of ectodermal structures.
Germ Layer: Ectoderm.
Abnormality: Sparse hair, missing teeth, no sweat glands.
Molecular Basis: Mutations in EDA, EDAR, EDARADD.
Physiology: Inability to sweat → heat intolerance.
Hypohidrotic Ectodermal Dysplasia
Cause: Weak dermal-epidermal junction.
Germ Layer: Ectoderm.
Abnormality: Fragile skin; blisters after minor trauma.
Molecular Basis: KRT5, KRT14 mutations (keratin).
Physiology: Chronic skin damage, pain, infection risk.
Epidermolysis Bullosa Simplex
Cause: Failure of neural crest cells to migrate to colon.
Germ Layer: Neural crest (ectoderm).
Abnormality: No ganglion cells in colon.
Molecular Basis: RET, EDNRB, GDNF gene mutations.
Physiology: Constipation, megacolon.
Hirschsprung Disease
Cause: Abnormal caudal mesoderm development.
Germ Layer: Mesoderm.
Abnormality: Malformed lower spine, kidneys, limbs.
Molecular Basis: Associated with maternal diabetes; HOX gene involvement.
Physiology: Limb paralysis, renal agenesis, bowel issues.
Caudal Dysgenesis
Cause: Vascular/mesodermal maldevelopment.
Germ Layer: Mesoderm.
Abnormality: Port-wine stains, varicosities, limb hypertrophy.
Molecular Basis: PIK3CA mutation.
Physiology: Limb asymmetry, bleeding, overgrowth.
Klippel-Trenaunay Syndrome
Cause: Improper heart tube fusion.
Germ Layer: Mesoderm.
Abnormality: Heart forms as two separate tubes.
Molecular Basis: NKX2.5, GATA4 defects.
Physiology: Incompatible with life due to failed heart formation.
Cardia Bifida
Cause: Failure of pleuroperitoneal membrane closure.
Germ Layer: Mesoderm.
Abnormality: Diaphragm defect → abdominal organs enter thorax.
Molecular Basis: FOG2, GATA4 mutations.
Physiology: Lung hypoplasia, respiratory distress.
Congenital Diaphragmatic Hernia
Cause: Disruption of embryonic blood supply.
Germ Layer: Mesoderm.
Abnormality: Absence of pectoralis major muscle; underdeveloped chest/limbs.
Molecular Basis: Unknown; vascular hypothesis.
Physiology: Chest asymmetry, arm weakness.
Poland Syndrome
Cause: Incomplete septum formation between ventricles.
Germ Layer: Mesoderm.
Abnormality: Hole in ventricular wall.
Molecular Basis: NKX2.5, GATA4, TBX5 mutations.
Physiology: Left-to-right shunt, heart failure.
Ventricular Septal Defect (VSD)
Cause: Failure of cloacal division into rectum and urogenital tract.
Germ Layer: Endoderm.
Abnormality: Absent or misplaced anal opening.
Molecular Basis: SHH, BMP4, HOX genes.
Physiology: Obstructed defecation; requires surgical correction.
Anorectal Malformation
Cause: Absence of pancreas formation.
Germ Layer: Endoderm.
Abnormality: No insulin/glucagon production.
Molecular Basis: PDX1, PTF1A, NEUROG3 mutations.
Physiology: Neonatal diabetes; digestive enzyme deficiency.
Pancreatic Agenesis
Cause: Incomplete separation of trachea and esophagus.
Germ Layer: Endoderm.
Abnormality: Blind-ending esophagus.
Molecular Basis: SOX2, TBX4, SHH genes.
Physiology: Choking, inability to feed, aspiration risk.
Esophageal Atresia
Cause: Failure of tracheoesophageal septum formation.
Germ Layer: Endoderm.
Abnormality: Abnormal connection between esophagus and trachea.
Molecular Basis: Similar to esophageal atresia.
Physiology: Aspiration pneumonia, feeding issues.
Tracheoesophageal Fistula
Cause: Incomplete obliteration of vitelline duct.
Germ Layer: Endoderm.
Abnormality: Ileal outpouching.
Molecular Basis: Developmental remnant.
Physiology: Can cause bleeding, obstruction, infection.
Meckel’s Diverticulum
Cause: Persistence of thyroglossal duct.
Germ Layer: Endoderm.
Abnormality: Cystic mass in midline neck.
Molecular Basis: Failed apoptosis of duct tissue.
Physiology: Swelling, infection, moves with swallowing.
Thyroglossal Duct Cyst
