RESUMEN
Deficiency in methylmalonyl-coenzyme A mutase (MCM) is associated with accumulation of methylmalonic acid (MMA) and clinical outcomes that include early death and neurological impairment. Reported here are two unrelated patients with a homozygous p.P86L mutation in the MUT gene, which encodes MCM, diagnosed following newborn screening. This is the first description of a homozygous mutation in the N-terminal extended segment of the MCM apoenzyme. Both in vitro and in vivo testing did not find a response to supplemental hydroxocobalamin. After discontinuation of hydroxocobalamin in one patient, serum MMA level remained elevated but stable, while urine MMA increased. Both patients have remained asymptomatic with normal development. The observed homozygous p.P86L mutation in the N-terminal extended segment may yield reduced MCM activity and is refractory to hydroxocobalamin supplementation, while not inducing a metabolically unstable phenotype. These genotype-phenotype associations further enhance the understanding of methylmalonic acidemia, which will continue to improve patient care.
Asunto(s)
Errores Innatos del Metabolismo de los Aminoácidos/genética , Metilmalonil-CoA Mutasa/genética , Mutación , Enfermedades Asintomáticas , Preescolar , Femenino , Homocigoto , Humanos , Recién Nacido , MasculinoRESUMEN
The mucopolysaccharidoses (MPS disorders) are rare inherited diseases associated with multi-organ accumulation of glycosaminoglycans, leading to musculoskeletal, respiratory, cardiac, neurological, ophthalmological, otolaryngological, and gastrointestinal abnormalities. As a result of improvements in diagnosis, multi-disciplinary care, and therapies such as enzyme replacement therapy and hematopoietic stem cell transplantation, an increasing number of patients with MPS are reaching adulthood and are involved in family planning. Data on fertility and pregnancy outcome in MPS is sparse and comprises primarily isolated case reports. To address this evidence gap, we present a case series on fertility and pregnancy in eight mothers and five fathers with MPS. This case series demonstrates that women with MPS have high-risk pregnancies and deliveries secondary to their underlying disease. However, with appropriate pre-conceptual multi-disciplinary evaluation, optimization and discussion regarding potential risks, combined with regular multi-disciplinary maternal and fetal surveillance in a tertiary center, the outcome of most pregnancies in this case series seems to be favorable with all babies developing normally. Partners of fathers with MPS had uncomplicated pregnancies and deliveries. All children were healthy, with normal growth and development.
RESUMEN
Abstract The mucopolysaccharidosis (MPS) disorders are rare genetic diseases caused by deficiencies in lysosomal enzymes involved in the degradation of glycosaminoglycans, leading to pulmonary, cardiac and neurological dysfunctions, skeletal anomalies, impaired vision, and/or hearing and shortened life spans. Whereas in the past, few individuals with MPS reached adulthood, better diagnosis, multidisciplinary care, and new therapies have led to an increasing number of adult patients with MPS. Therefore, fertility and pregnancy questions in this patient population are becoming more important. Management of fertility issues and pregnancy in patients with MPS is challenging due to the lack of documented cases and a dearth in the literature on this topic. This review presents multidisciplinary expert opinions on managing fertility and pregnancy based on case studies and clinical experience presented at a meeting of MPS specialists held in Berlin, Germany, in April 2015. An overview of the existing literature on this subject is also included.