[...]... proportion of cases involving consanguinity is also reported to be about one-third, it is difficult to determine if mental retardation in individuals with ABL is due to the disease itself or to other effects of consanguinity Consanguinity may also be responsible for other birth defects seen infrequently in ABL GALE ENCYCLOPEDIA OF GENETIC DISORDERS The diagnosis of ABL is suspected from the intestinal,... with achondrogenesis may have the condition polyhydramnios, a condition in which there is too much fluid around the fetus in the amniotic GALE ENCYCLOPEDIA OF GENETIC DISORDERS KEY TERMS Chondrocyte—A specialized type of cell that secretes the material which surrounds the cells in cartilage Fetal hydrops—A condition in which there is too much fluid in the fetal tissues and/or cavities Micromelia The. .. some individuals will have mild impairments There does not appear to be any particular 2 association with behavioral disturbances However, attention deficit occurs among some boys with learning difficulties Diagnosis The diagnosis of Aarskog syndrome is made on the basis of clinical findings, primarily analysis of the family history and characteristic facial, skeletal, and genital findings There are... partial ability to produce a particular enzyme may not show the effects of this deficiency until their need for the enzyme, because of growth or maturation, has outpaced their ability to produce it The level of ability of individuals with acid maltase deficiency to produce acid maltase, or their ability to sustain existing levels of acid maltase, are the sole determinants of the severity of the observed... state of having extremely short limbs Ossification The process of the formation of bone from its precursor, a cartilage matrix Polyhadramnios—A condition in which there is too much fluid around the fetus in the amniotic sac sac, and/or fetal hydrops, a condition in which there is too much fluid in the fetal tissues and/or cavities Infants with achondrogenesis are also often born in the breech position... meaning they dissolve in lipids in order to be used by the body Low lipid levels in the blood means that people with ABL have chronic deficiencies of vitamins A, E, and K Much of the neuromuscular disease seen in ABL is thought to be caused by deficiencies of these vitamins, especially vitamin E Approximately one-third of all individuals with ABL develop mental retardation However, since the proportion... upper incisors The fingers are often held in a distinctive position with flexion at the joint between the hand and the fingers, over extension at the first joint of the finger and flexion at the second joint This hand posturing becomes more obvious when there is an attempt to spread the fingers There may also be some mild webbing between the fingers The fingers are short and there is often only a single... children with achondroplasia and their families should be closely monitored Children with visible physical differences can have difficulties in school and socially Support groups such as Little People of America can be a source of guidance on how to deal with these issues It is important that children with achondroplasia not be limited in activities that pose no danger In addition to monitoring their social... pregnancy in GALE ENCYCLOPEDIA OF GENETIC DISORDERS Acardia an epileptic mother who took primidone, a seizure medication, in the first trimester of her pregnancy Another report, in 2000, describes an acardiac twin pregnancy in an epileptic mother who took a different seizure medication, oxcarbazepin Diagnosis A mother carrying an acardiac twin pregnancy is not likely to have any unusual symptoms An acardiac... Diagnostics SUNY Upstate Medical University Syracuse, NY Kevin M Sweet, MS CGC Cancer Genetic Counselor James Cancer Hospital Ohio State University Columbus, OH Catherine Tesla, MS CGC Senior Associate, Faculty Dept of Pediatrics, Division of Medical Genetics Emory University School of Medicine Atlanta, GA GALE ENCYCLOPEDIA OF GENETIC DISORDERS Oren Traub, MD PhD Resident Physician Dept of Internal Medicine . provider. GALE ENCYCLOPEDIA OF GENETIC DISORDERS vii PLEASE READ—IMPORTANT INFORMATION The Gale Encyclopedia of Genetic Disorders is a unique and invaluable source for information regarding diseases. DISORDERS xi Introduction Stephen Braddock, MD Assistant Professor Director, Missouri Teratogen Information Service (MOTIS) Division of Medical Genetics University of Missouri-Columbia School of Medicine Columbia,.