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Biomedical subjects

C A Francomano

Publications and source records attributed to C A Francomano.

100 records · Page 6Linked to original sources
PubMed1988

Therapeutic approaches to cobalamin-C methylmalonic acidemia and homocystinuria.

The use of hydroxocobalamin (OH-B12), betaine, carnitine, and folinic acid were studied in two children with the cobalamin C form of methylmalonic acidemia and homocystinuria. When daily injections of 1 mg OH-B12 were discontinued for 3 weeks, there was no significant change in total plasma homocysteine or methionine levels and only a modest increase in methylmalonate. Orally administered OH-B12 1 mg/d in one patient was associated with an increase in plasma homocystine and a decrease in methionine within 1 month. Withdrawal of betaine 250 mg/kg/d was also associated with a rise in plasma homocystine and a fall in methionine levels. Carnitine 100 mg/kg/d lead to an increase in urinary excretion of propionylcarnitine, but did not affect plasma methylmalonate levels. No beneficial biochemical effect of folinic acid could be documented at a dose of 25 mg/d. Our results suggest that daily injections of OH-B12 are not necessary to maintain metabolic control and that orally administered OH-B12 is unlikely to be effective. Betaine appears to act synergistically with OH-B12 and should be part of the treatment regimen. Although there are theoretical reasons for using L-carnitine and folinic acid, we could not document their effectiveness in these two patients.

Administration, Oral↗
PubMed1987

Partial structure of the human alpha 2(IV) collagen chain and chromosomal localization of the gene (COL4A2).

We have isolated a 2.1-kb cDNA clone from a human placental library encoding part of the alpha 2 chain of collagen IV, a major structural protein of basement membranes. The DNA sequence encodes 446 amino acids in the triple-helical domain plus the 227 amino acids of the carboxy-terminal globular domain. The latter structure is composed of two homologous subdomains and is highly conserved between the alpha 1 and alpha 2 chains. The triple-helical domain contained seven interruptions of the Gly-X-Y repeat and these interruptions were in general larger than their counterparts in the alpha 1 chain. DNA from human rodent hybrid cell lines was analyzed under conditions in which there was no cross-hybridization of the alpha 2(IV) cDNA probe with the gene for the alpha 1(IV) collagen chain. An EcoRI fragment characteristic of the alpha 2 chain had a concordance of 0.97 with chromosome 13. This result was confirmed and extended with in situ localization of the gene at 13q34. Since the alpha 1(IV) gene has previously been localized to 13q34, the two type IV collagen genes reside in the same chromosome region (13q34), possibly in a gene cluster. The presence of the genes for type IV collagen chains on chromosome 13 excludes a primary role for these genes in adult polycystic kidney disease and X-linked forms of hereditary nephritis.

Amino Acid Sequence↗
PubMed1987

The Stickler syndrome: evidence for close linkage to the structural gene for type II collagen.

The Stickler syndrome is an autosomal dominant hereditary disorder of connective tissue with pleiotropic features including premature osteoarthropathy, mild spondyloepiphyseal dysplasia, vitreoretinal degeneration, and the Pierre-Robin sequence. Genetic linkage studies in two families with the Stickler syndrome have been performed using restriction fragment length polymorphisms associated with the structural gene for type II collagen, COL2A1. No recombinants between the Stickler phenotype and COL2A1 were observed. The total LOD score for linkage of the Stickler syndrome and COL2A1 at a recombination fraction (theta) of zero is 3.59. These findings suggest that, at least in some families, the mutation causing Stickler syndrome affects the structural locus for type II collagen.

Collagen↗
PubMed1987

Mortality in achondroplasia.

Standardized mortality ratios (SMRs) were determined for a historical cohort of achondroplastic individuals identified through the Medical Genetics Clinics of the University of Texas Health Science Center at Houston and Johns Hopkins Hospital, Baltimore. Mortality was increased at all ages, with an overall SMR of 2.27 (95% confidence interval 1.7-3.0). Sudden death accounted for the excess deaths in those less than 4 years of age, and brain-stem compression was identified as the cause in half of these deaths. Central nervous system and respiratory causes were not significantly increased but accounted for half of the deaths in those 5-24 years of age. SMRs were not significantly increased for those greater than 34 years of age. However, deaths attributed to cardiovascular causes were increased in the 25-54-year-old age group, accounting for 10 of 17 deaths. The overall cardiovascular SMR was 5.2 (95% confidence interval 2.5-9.6). Within this group, severe disability resulting from marked spinal canal stenosis was present in a majority of individuals and may have been a contributing factor in these deaths. This study suggests that the bony abnormalities associated with achondroplasia--i.e., foramen magnum and spinal canal stenosis--may have a significant effect on mortality at all ages but particularly in children. Efforts to minimize these complications are recommended.

Achondroplasia↗
PubMed1986

DNA analysis in genetic disorders.

Recombinant DNA technology has applications in the analysis of an ever-increasing number of genetic disorders. This review discusses the basic genetic principles underlying recombinant DNA techniques, the general approach to analyzing genetic disorders using these methods, and finally the practical applications of DNA analysis in genetic disease.

Child↗
PubMedDate not supplied

A comparison of the Berlin and Ghent nosologies and the influence of dural ectasia in the diagnosis of Marfan syndrome.

PURPOSE: To compare the Berlin and Ghent diagnostic criteria for Marfan syndrome and evaluate the utility of screening for dural ectasia in the diagnosis of Marfan syndrome. METHODS: Review of clinical and radiographic data on 73 patients evaluated for Marfan syndrome at the National Institutes of Health. RESULTS: Nineteen percent of patients diagnosed under the Berlin criteria failed to meet the Ghent standard. Dural ectasia was the second most common major diagnostic manifestation, and screening for dural ectasia established the diagnosis of Marfan syndrome in 23% of patients under the Ghent criteria. CONCLUSIONS: Some patients are appropriately excluded from the diagnosis of Marfan syndrome by the Ghent criteria. Determination of dural ectasia is valuable in the diagnosis of Marfan syndrome.

Diagnosis, Differential↗
PubMedDate not supplied

The hip in Stickler syndrome.

Stickler syndrome is an autosomal dominant connective tissue disorder with a prevalence similar to that of Marfan syndrome. No previous study has examined hip pain or abnormalities in a large series of patients with Stickler syndrome. The purpose of this study was to describe hip abnormalities and their correlation with age and chronic hip pain in a cohort of 51 patients followed at the National Institutes of Health. Ten percent of patients had protrusio acetabuli, 21% coxa valga, and 34% of adults had hip osteoarthritis. Sixty-three percent of all patients and 79% of adults had chronic hip pain. In addition, 16% of adult patients had a history of femoral head failure during youth. Arthritic changes and adult age were associated with hip pain. In summary, hip abnormalities are commonly observed in Stickler syndrome. Young patients require careful evaluation of hip pain, and regular screening of children with Stickler syndrome may be indicated for early detection of hip complications.

Abnormalities, Multiple↗