Human Genetics and Disorders

This is the correct option. Acute diseases are those diseases whose symptoms are quickly visible in the body. Congenital diseases are caused due to the genetic abnormalities, metabolic disorders or malfunctioning of any organ. Acquired diseases are those which develop after birth.

Lysosomal Storage Disorders are characterized by deficiency of specific lysosomal hydrolase enzymes, leading to accumulation of substrates within lysosomes. The primary defect is the absence or dysfunction of these hydrolytic enzymes. Options B and C describe other possible lysosomal dysfunctions but are not the defining feature of LSDs. Option D is incorrect because the enzyme deficiency (Option A) is the hallmark of these disorders.

Lysosomal storage disorders are caused by deficiency of specific hydrolytic enzymes within lysosomes. This leads to accumulation of substrates that would normally be degraded. The primary defect is not in lysosomal membrane structure or fusion with phagosomes - the core issue is missing or deficient hydrolase enzymes.

Senile cardiac amyloidosis is caused by deposition of transthyretin (TTR) amyloid in the heart, particularly in elderly patients. This is distinct from secondary amyloidosis (AA protein from chronic inflammation) and dialysis-associated amyloidosis (beta-2 microglobulin). Transthyretin is a transport protein produced in the liver that can misfold and deposit as amyloid fibrils.

Linkage analysis tracks DNA polymorphisms (markers) that co-segregate with a disease phenotype within families. It identifies chromosomal regions harboring disease genes by observing inheritance patterns. It doesn't directly make pedigree charts (that's done separately) or detect non-paternity.

Alexander's disease (a leukodystrophy caused by GFAP mutations) classically presents with extensive white matter involvement and characteristic frontal-predominant changes, with MRI showing hyperintense lesions that commonly involve the thalami and basal ganglia. The pattern of extensive deep white matter hyperintensity with thalamic involvement is highly suggestive of Alexander disease, differentiating it from other leukodystrophies which have different distribution patterns.

Bladder exstrophy carries the highest risk of urothelial cancer among urogenital anomalies due to chronic inflammation and prolonged exposure of urothelium to urine. The other conditions (medullary sponge kidney, renal agenesis, double ureter) do not significantly increase urothelial cancer risk.

Leukotrichia (white hair in vitiligo patches) indicates destruction of melanocytes in hair follicles, which is a POOR prognostic sign as it means vitiligo is more stable and resistant to treatment. All other statements are true: vitiligo has genetic predisposition, UVB therapy is a mainstay treatment, and local steroids are used. The question asks which is NOT true.

This is true during fertilization.

Achondroplasia is an autosomal dominant disorder. When healthy (normal height) parents produce a child with achondroplasia, it results from a spontaneous (new) mutation in the gametes or early embryo. Point mutation is a type of mutation mechanism, while induced mutation refers to artificially caused changes.

Albinism is caused by defective melanin production due to deficiency of the enzyme tyrosinase (also called tyrosine 3-monooxygenase). This enzyme converts tyrosine to DOPA in the melanin synthesis pathway. Without functional tyrosinase, melanin cannot be produced, resulting in absence of pigment in skin, hair, and eyes. The other enzymes listed are involved in different metabolic pathways: homogentisic acid oxidase in tyrosine breakdown, phenylalanine hydroxylase in phenylalanine metabolism, and thiamine pyrophosphate is a coenzyme.

Marfan syndrome is an autosomal dominant connective tissue disorder affecting multiple systems including eyes (lens dislocation), cardiovascular system (aortic aneurysm, valve problems), and skeletal system (tall stature, scoliosis, hyperflexible joints). Since it affects all these systems, 'All of the above' is the correct answer.

Color blindness (specifically red-green color blindness) is a sex-linked trait carried on the X chromosome. Males (XY) are more frequently affected because they have only one X chromosome. Beri beri is a vitamin deficiency, tylosis is an autosomal dominant condition affecting esophagus skin, and albinism is an autosomal recessive trait - none of these are sex-linked.

Color blindness is a classic X-linked recessive trait - the gene is located on the X chromosome, making it sex-linked. Males (XY) express it with one affected X, while females (XX) need two affected X chromosomes. Baldness is sex-influenced (hormone-modified) rather than sex-linked. Diabetes is polygenic/multifactorial and polio is an infectious disease, neither being sex-linked genetic conditions.