Question

A child has phenylketonuria (PKU). The healthcare professional educates the parents on the special diet needed, telling them that children with PKU are unable to synthesize what?

		Essential amino acid, phenylalanine, to tyrosine
		Renin, erythropoietin, and antidiuretic hormone
		Aldosterone, cortisol, and androgens
		Neurotransmitters gamma-aminobutyric acid (GABA) and acetylcholine

What is the effect of low plasma albumin?

		Clotting factors decrease, thus increasing the chance of prolonged bleeding.
		Fewer immunoglobulins are synthesized, thus impairing the immune function.
		Less iron is stored, thus increasing the incidence of iron deficiency anemia.
		Osmotic pressure decreases; thus water moves from the capillaries to the interstitium.

A child has Duchenne muscular dystrophy and the parents want to know how this occurred. Which statement by the healthcare professional is most accurate?

		X-linked recessive inheritance
		Common SMN1 gene abnormality
		Autosomal dominant inheritance
		Inheritance is not well defined

Answer 1

Question 1

Answer:-child will not be able to convert phenyl alanine to tyrosine

Conversion of phenylalanine to tyrosine take place with the help of the enzyme phenylalanine hydroxylase.The genetic mutation in phenylketonuria causes either absence of synthesis of enzyme or synthesis of a non functional enzyme.This causes accumulation of phenylalanine. Alternate pathways are opened and phenylketones are produced (phenyl lactic acid, phenyl pyruvic acid, phenyl acetic acid).Phenylalanine levels in blood rises, and phenyl ketones are excreted in urine.Child will be mentally retarded,there will be convulsions, tremor,agitation,hypo pigmentation, mousy odour in sweat due to phenyl lactic acid.Diet low in phenyl alanine is to be advised.This special diet has to be taken for the first decade of life.

Question 2

Answer:- osmotic pressure decreases and thus water moves from the capillaries to the interstitium

Albumin is a plasma protein synthesised in liver.Plasma proteins are responsible for maintaining the osmotic pressure in the capillaries.When albumin synthesis is affected ,the colloid osmotic pressure falls. This causes increased capillary filtration throughout the body and extracellular oedema. This explains the edema caused by cirrhosis of liver.

Question 3

Answer:-X linked recessive inheritance

DMD is a hereditary myopathy.It is an X linked recessive muscular dystrophy caused due to mutation in dystrophin gene.It is the most common mutational disease affecting boys.Proximal muscles especially of lower extremities is affected first.Affected boys will have difficulty climbing stairs and can't run well.Gradually there will be generalised weakness. Hypertrophy of calf muscles is an early finding. Disease manifestations are first seen usually between 5 and 15 .There will be mental retardation as well as cardiac involvement.