6q24-TNDM is defined as transient neonatal diabetes mellitus caused by genetic aberrations of the imprinted locus at 6q24. The cardinal features are: severe intrauterine growth retardation, hyperglycemia that begins in the neonatal period in a term infant and resolves by age 18 months, dehydration, and absence if ketoacidosis. Macroglossia and umbilical hernia are often present. Diabetes mellitus usually starts within the first week of life and lasts on average three months but can last over a year. Although insulin is usually required initially, the need for insulin gradually declines over time. Intermittent episodes of hyperglycemia may occur in childhood, particularly during intercurrent illnesses. Diabetes mellitus may recur in adolescence or later in adulthood. The average age of recurrence in the series was 14 years, coinciding with puberty. Some require insulin, others are treated with oral drugs or diet alone. Intelligence and growth are usually normal in this condition except in individuals with loss of methylation at multiple loci. Prevalence of TNDM in the UK was initially estimated at 1:400,000 as reported in 1997. More recent calculations confirm a total neonatal diabetes incidence of 1:215,000 to 1:400,000 (2004-2010). Blood glucose concentration should be monitored and insulin doses changed accordingly as in the standard treatment for diabetes mellitus. Insulin can be discontinued when blood glucose concentrations stabilize. Once diabetes mellitus is in remission, parents need to be alerted to the possibility of recurrence of the diabetes mellitus, particularly during periods of illness. If diabetes mellitus recurs, treatment may require diet alone, oral agents, or insulin, although the doses of insulin needed tend to be less than those required in Type 1 diabetes mellitus. The risk to parents, sibs, and offspring of a pro band with TNDM (transient neonatal diabetes mellitus) caused by paternal UPD6(Uniparental disomy 6) is unlikely to be higher than the risk to the general population, as paternal UPD6 is a de novo, typically non-recurrent event. Each child of a male with 6q24-TNDM caused by duplication of 6q24 has a 50% chance of inheriting the duplication and is at high risk of developing 6q24-TNDM and/or diabetes mellitus later in life.
References & Website with full article:
http://www.ncbi.nlm.nih.gov/books/NBK1534/?report=printable
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