Lymphoid Organ Development/Lymphopoeisis

Question 1

DiGeorge Syndrome

Answer 1

Infants born without thymus and parathyroid gland, and have defects in their cardiac outflow tracts.

Clinical Characteristics: Congenital hypoparathyroidism, increased susceptibility to infections, anomalies of the mouth (shortened philtrum of upper lip [fish-mouth deformity]), low set notched ears, nasal clefts, thyroid hypoplasia, and cardiac abnormalities (defects of the arch of the aorta).

Occurs because the third and fourth pharyngeal arches fail to differentiate into the thymus and parathyroid glands. This is caused by a breakdown in signaling between pharyngeal endoderm and adjacent neural crest cells.

Facial abnormalities result primarily from abnormal development of the first arch components because neural crest cells are disrupted, and the cardiac anomalies arise in those sites normally occupied by neural crest cells.

In most cases, there is a micro deletion in the q11.2 region of chromosome 22, HIRA and UFDIL gene mutation, and neural crest cell deficits. Origin is form either parent.

Question 2

Isotretinoin (13 -cis-retinoic acid)

Answer 2

THYMIC APLASIA, craniofacial abnormalities, NTD such as spina bifida cystica, cardiovascular anomalies, cleft palate.

Question 3

Cytomegalovirus

Answer 3

Microcephaly, chorioretinitis, sensorineural hearing loss, delayed psychomotor/mental development, HEPATOSPLENOMEGALY, hyrdrocephaly, cerebral palsy, brain (periventricular) calcification

Question 4

Rubella Virus

Answer 4

IUGR, postnatal growth retardation, cardiac and great vessel abnormalities, microcephaly, sensorineural deafness, cataract, microphthalmos, glaucoma, pigmented retinopathy, mental deficiency, neonate bleeding, HEPATOSPLENOMEGALY, osteopathy, tooth defects

Question 5

Hepes Simplex Virus

Answer 5

Skin vesicles and scarring, chorioretinitis, HEPATOMEGALY, THROMBOCYTOPENIA, petechiae, hemolytic anemia, hydranencephaly

Question 6

Warfarin

Answer 6

Nasal hypoplasia, stripples epiphyses, hypoplastic phalanges, eye anomalies, mental deficiency, and HEMORRHAGE

Question 7

Methotrexate

Answer 7

Multiple defects, especially skeletal, involving face, cranium, limbs, and vertebral column. It is an an antineoplastic agent.

Question 8

Corticosteroids

Answer 8

Fetal Bleeding

Question 9

Thalidomide

Answer 9

Abnormal development of limbs,e.g meromelia (partial absence) and amelia (complete absence); facial defects, systemic anomalies, e.g. carida, kidney, and ocular defects. HEMANGIOMA ON FOREHEAD