True statement regarding Bloom syndrome is:
Ref: Robbins Pathologic Basis of Disease, 8th editionExplanation:Bloom syndrome (congenital telangiectatic erythema)It is a rare autosomal recessive disorderIt is characterized by:TelangiectasiaPhotosensitivityGrowth deficiency of prenatal onsetImmunodeficiencyIncreased susceptibility to neoplasmsHistoryPhysical features of Bloom syndrome (congenital telangiectatic erythema).Growth delay has a prenatal onset and persists throughout life.More than half the children are significantly underdeveloped in physical stature until age 8 years.NeoplasiaPatients have an overall 150 - to 300-times increased risk of malignancy compared with the general population.20% of patients develop malignancies fe.g. acute leukemia, lymphoma, gastrointestinal adenocarcinoma).Immunology:Decreased Ig A and Ig MRecurrent respiratory and gastrointestinal tract infections.Skin findingsTelangiectatic erythema appears as macules or plaques in a butterfly distribution on the face and other photodistri- huted areas.Eyes may have scleral telangiectases.Cheilitis with crusting or bleeding is present.Cafe au lait macules with adjacent hypopigmented areas appear as 'twin spotting'.Craniofacial/body habitusLack of subcutaneous fat contributes to a characteristic bird I ike facies with a long, narrow face and prominent nose.The skull shape is dolichocephalicPatients have malar hypoplasia and small mandibles.Affected individuals have relatively large protruding ears.Long limbs, disproportionally large hands and feet, and progressive contracture of hands and feet are noted.Upper extremities are long in proportion to body length.Quick, birdlike movements are characteristic.Patients have short stature.Ear, nose, and throat: Patients have a high- pitched voice.Endocrine: Patients have primary hypogonadism .CausesAutosomal recessive pattern of inheritance.The gene locus is band I5q26.1.Cytogenetic findings in a Bloom syndrome patient with AML subtype Ml showed preferential occurrence of total or partial loss of chromosome 7.Mutation of the DNA ligase I geneLaboratory StudiesChromosome study: blood and skin cells show a characteristic pattern of chromosome breakage and rearrangement.Testing for chromosome instability, including the presence of quadriradicals and increased sister chromatid exchanges.Immunoglobulin levels (Decreased IgA & IgM)Medical CareHas no specific treatmentAvoiding sun exposure and using sunscreens can help prevent some of the cutaneous changes associated with photosensitivity.
Raised Ig M
Absent Ig A
Decreased IgM
Raised Ig E
Cytogenetic Disorders