Congenital deficiency

Congenital deficiency of prothrombin is inherited in an autosomal recessive fashion and is the rarest of all the hereditary coagulation disorders. Congenital dysprothrombinemia has also been recognized. 

Congenital deficiency of Factor IX results in hemophilia B, also known as Christmas disease, and is inherited in a sex-linked recessive manner. Instmctive is the fact that some female carriers are symptomatic. Combined deficiencies of Factors VIIFC and IX have been described. 

Congenital deficiency of Factor X is a rare autosomal recessive disorder. Several variants have been described. 

Congenital deficiency of Factor XI is a relatively rare coagulopathy that has been reported as both an autosomal dominant and autosomal recessive trait. This deficiency state occurs predominantly in the Jewish population. Most patients with this deficiency state remain asymptomatic until trauma or surgery is encountered. Spontaneous hemorrhage is rare in this population. 

Congenital deficiency of Factor XII is inherited as an autosomal recessive trait. Deficiency of this factor is rarely associated with any coagulopathy. It has been observed that people deficient in this factor may have an increased frequency of thromboembolic compHcations. 

Congenital deficiency of Factor Xlll is inherited as an autosomal recessive trait and is frequendy recognized at birth because of delayed persistent hemorrhage from the umbiUcus. In Factor Xlll-deficient people wound healing is defective and wound dehiscence is common. 

Phenylketonuria usually is caused by a congenital deficiency of phenylalanine hydroxylase 672... 

On rare occasions an organic aciduria occurs not because of an enzyme deficiency but from a failure to transport or activate a water-soluble vitamin that serves as a cofactor for the reaction in question. Thus, congenital deficiencies in the metabolism of vitamin B12 commonly give rise to methylmalonic aciduria (Fig. 40-1, Table 40-2). Similarly, deficiencies of biotin metabolism can cause a severe organic aciduria (Table 40-2). It is very important to be aware of the defects of vitamin metabolism because the administration of large doses of these cofactors may completely prevent brain damage. 

Phenylketonuria usually is caused by a congenital deficiency of phenylalanine hydroxylase. Phenylketonuria (PKU) is among the more common aminoacidurias (-1 20,000 live births). The usual cause is a nearly complete deficiency of phenylalanine hydroxylase, which converts phenylalanine into tyrosine (Fig. 40-2 reaction 1). 

FIGURE 40-2 The phenylalanine hydroxylase (PAH) pathway. Phenylketonuria usually is caused by a congenital deficiency of PAH (reaction 1), but it also can result from defects in the metabolism of biopterin, which is a cofactor for the hydroxylase. Enzymes (1) Phenylalanine hydroxylase (2) Dihydropteridine reductase (3) GTP cyclohydrolase (4) 6-pyruvoyltetrahydrobiopterin synthase. BH4, tetrahydrobiopterin DEDT, o-erythro-dihydroneopterin triphosphate QH2, dihydrobiopterin. 

The most common cause of homocystinuria is a congenital deficiency of cystathionine-p-synthase, a pyridoxine-dependent enzyme that condenses homocysteine and... 

The possibility of gene therapy for these disorders is a subject of intense scrutiny [38]. An adenoviral vector containing a cDNA for the OTC gene has been given to mice with a congenital deficiency of OTC. The result was... 

A child is diagnosed with a congenital deficiency of medium-chain acyi-CoA dehydrogenase activity. Which of the following signs or symptoms would most likely occur upon fasting in this child ... 

BemardSoulier syndrome Defect or congenital deficiency in GPIb/IXAl complex... 

Mechanism of overproduction of purine nucleotides in the congenital deficiency of hypoxanthine-guanine phosphoribosyltransferase. The loss of the transferase prevents the recycling of hypoxanthine and guanine. This increases uric acid production as well as the de novo synthesis of purine nucleotides. 

Watanabe, N., Nawa, Y., Okamoto, K. and Kobayashi, A. (1 994) Expulsion of Hymenolepis nana from mice with congenital deficiencies of IgE production or of mast cell development. Parasite Immunology 1 6, 1 37-144. 

The risk of thromboembolic complications when diethylstilbestrol is used in treating prostatic cancer is well documented, but there has been some doubt as to the mechanisms involved. Oral diethylstilbestrol diphosphate 300 mg/day has been compared with LR-RH agonist therapy or no treatment in 35 patients with prostatic cancer (5). Diethylstilbestrol reduced the concentrations of protein S to below the lower limit of normal in 24 of the 35 cases. There was also some reduction in antithrombin III concentrations. These results were consistently confirmed in a follow-up group of eight further patients who took diethylstilbestrol. Since these very low concentrations of protein S are virtually the same as those found in congenital deficiency, it seems likely that this plays a role in the development of cardiovascular complications during diethylstilbestrol treatment. 

Vitamin B12 deficiency also occurs when the region of the distal ileum that absorbs the vitamin B12-intrinsic factor complex is damaged, as when the ileum is involved with inflammatory bowel disease, or when the ileum is surgically resected. In these situations, radioactively labeled vitamin B12 is not absorbed in the Schilling test, even when intrinsic factor is added. Other rare causes of vitamin B,2 deficiency include bacterial overgrowth of the small bowel, chronic pancreatitis, and thyroid disease. Rare cases of vitamin B12 deficiency in children have been found to be secondary to congenital deficiency of intrinsic factor and congenital selective vitamin Bi2 malabsorption due to defects of the receptor sites in the distal ileum. 

Human populations that have experienced health effects from exposure to 2-nitrophenol or 4-nitrophenol have not been identified, but little research has been conducted on this subject. Based on results from animal studies, as described in Section 2.6, it is possible that individuals who consume ethanol may have slower rates of clearance of 4-nitrophenol. This subpopulation, if exposed to 4- nitrophenol, may be considered potentially susceptible. Furthermore, newborn infants utilize fetal hemoglobin, which has reduced oxygen-carrying capacity, and also have low levels of nicotinamide adenine dinucleotide diaphorase, which continuously reduces methemoglobin therefore, infants (as well as individuals congenitally deficient in this enzyme) may represent... 

In mammals and birds, there are four biotin-dependent carboxylases acetyl CoA carboxylase, pyruvate carboxylase, propionyl CoA carboxylase, and methylcrotonyl CoA carboxylase. Congenital deficiency of three of the four human biotin-dependent carboxylases has been reported. 

Biotinidase functions both to release free biotin from biocytin in foods, and to recycle and conserve biotin after turnover of biotin-containing enzymes. As discussed in Section 11.2.3.1, rare congenital deficiency of biotinidase results in severe functional biotin deficiency. 

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