1. DISEASE CHARACTERISTICS
1.1 Name of the disease (synonyms)
6q24 Transient Neonatal Diabetes Mellitus (6q24 TNDM or TNDM1); Diabetes Mellitus, Transient Neonatal (TND, DMTN); Imprinted transient neonatal diabetes (iTND).
1.2 OMIM# of the disease
1.3 Name of the analysed genes or DNA/Chromosome segments
6q24; PLAGL1 Imprinting control region (ICR); ZFP57.
1.4 OMIM# of the gene(s)
PLAGL1, 603044; HYMAI, 606546; ZFP57, 612192.
1.6 Analytical methods
DNA methylation analysis can be performed by ASMM RTQ-PCR; MS-MLPA (SALSA kit ME032 (MRC-Holland, Amsterdam, The Netherlands)); MS-PCR, bisulphite pyrosequencing, MS-SnuPE and methylation array.3, 4, 5, 6, 7 Copy number imbalance can be detected by MS-MLPA, short tandem repeat marker typing and molecular karyotyping (SNP array, aCGH), and in the case of rare large duplications, FISH or cytogenetic analysis. Uniparental disomy analysis can be performed by short tandem repeat marker typing or by molecular karyotyping using SNP array (UPD testing should preferentially include the parents for full informativity).
1.7 Analytical validation
Parallel analysis of negative (unaffected) and positive (affected) controls. Determination of methylation and copy number reference ranges in unaffected individuals (for methylation of same tissue type). For methylation analysis fully (in vitro) methylated and unmethylated (eg, whole-genome amplification) controls should be included.
1.8 Estimated frequency of the disease
1.9 Diagnostic setting
Comment: Prenatal testing may in principle be requested, in cases of familial chromosomal rearrangements potentially affecting the copy number of PLAGL1 or leading to UPD of this region, as well as in cases of familial ZFP57 mutations. In practice, the rarity of the disorder makes prenatal testing extremely rare. In principle, prenatal testing for genomic disturbances (duplications, point mutations) can be offered without limitations and can support clear genetic counselling. Prenatal methylation-specific testing is not common, due to insufficient knowledge about the prenatal setting of the PLAGL1 imprinting mark. Special consideration of recurrence risk is required for the rare maternal effect mutations in NLRP2, NLRP7 or KHDC3L (see Section 3.4).
2.1 Analytical sensitivity
(proportion of positive tests if the genotype is present to the best of our knowledge at the moment given that the condition is so rare)
2.2 Analytical specificity
(proportion of negative tests if the genotype is not present)
2.3 Clinical sensitivity
(proportion of positive tests if the disease is present)
Note that neonatal diabetes is genetically heterogeneous and, besides the 6q24-linked form described in this gene card, includes other monogenetic forms.9, 10, 11 Mutations of ABCC8 (MIM#600509) and KCNJ11 (MIM#600937) account for ∼30% of TNDM, but have a distinct clinical history, with less-extreme low birthweight, and later onset and remission.2, 10 Moreover, forms of permanent NDM exist. If these monogenetic forms being part of the differential diagnoses are not considered, the sensitivity (ie, 6q24 aberration detected by test if the disease is present) is estimated to be 70–80%
2.4 Clinical specificity
(proportion of negative tests if the disease is not present)
2.5 Positive clinical predictive value
(lifetime risk to develop the disease if the test is positive)
A small number of cases (n=3 in a cohort of 163 cases) have been described where individuals with 6q24 TNDM mutations did not present neonatally, but subsequently, with disorders such as insulin resistance or gestational diabetes.12, 13 Owing to the rarity of the disorder, the lifetime risk of later presentation in these individuals is not established.
Note that diabetes presenting at birth resolves in the first few months of life. Earlier clinical studies indicated that ∼50% of individuals presenting neonatally with 6q24 TNDM would subsequently develop a disorder akin to type 2 diabetes, in later childhood or adulthood,14 but there is no definitive research to confirm this.
2.6 Negative clinical predictive value
(Probability not to develop the disease if the test is negative)
Index case in that family had been tested:
Approaching 100%, where the proband has a positive diagnosis of a 6q24 anomaly.
Index case in a family that has not been tested:
Where a proband has a clinical diagnosis of transient neonatal diabetes but no molecular diagnosis has been performed, then the molecular cause may be 6q24 aberration, or mutation in ABCC8/KIR6.2. In a hyperglycaemic infant under 6 months of age, molecular diagnoses of both transient and permanent neonatal diabetes should be considered.9
3. Clinical Utility
3.1 (Differential) diagnostics: The tested person is clinically affected
(To be answered if in 1.9 ‘A’ was marked)
3.1.1 Can a diagnosis be made other than through a genetic test?
3.1.2 Describe the burden of alternative diagnostic methods to the patient
A diagnosis of neonatal diabetes can be made clinically in infants under 6 months of age, with combined biochemical and immunological (absence of antibodies, no HLA-association) analysis; however, genetic diagnosis is warranted for differentiating 6q24 TNDM from other (monogenic) causes of TNDM where clinical history and management are different.9 Moreover, molecular testing enables differential diagnosis at manifestation (when the transient nature is not known) between transient and permanent neonatal diabetes.
3.1.3 How is the cost effectiveness of alternative diagnostic methods to be judged?
3.1.4 Will disease management be influenced by the result of a genetic test?
3.2 Predictive setting: The tested person is clinically unaffected but carries an increased risk based on family history
(To be answered if in 1.9 ‘B’ was marked)
3.2.1 Will the result of a genetic test influence lifestyle and prevention?
If the test result is positive (please describe):
If the test result is positive, there is an ∼50% risk of non-insulin-dependent diabetes developing in adolescence or adulthood. The predisposing factors are not fully understood, but diabetes may be precipitated by metabolic stresses such as puberty, pregnancy, illness or predisposing lifestyle factors. Therefore, those very rare individuals with a positive test result but without neonatal presentation (Section 2.5) should be vigilant for signs of incipient diabetes.
If the test result is negative (please describe):
3.2.2 Which options in view of lifestyle and prevention does a person at-risk have if no genetic test has been done (please describe)?
(i) In a pedigree with an intrachromosomal duplication of PLAGL1, a male has a 50% risk of transmitting a duplicated allele to offspring, whether his own duplication was maternally or paternally transmitted. In case of interchromosomal changes leading to gain of 6q24 the segregation might be dependent on the size of the exchanged fragments. Carriers of a balanced translocation affecting chromosome 6 have an increased risk for their offspring carrying an unbalanced aberration of 6q24, which in case of paternal gain leads to 6q24 TNDM. Similarly, there is theoretically an increased risk for UPD(6q24)pat due to trisomy/monosomy rescue. (ii) In a pedigree with ZFP57 mutation, homozygous individuals are at risk of 6q24 TNDM.
3.3 Genetic risk assessment in family members of a diseased person
Most molecular aberrations in 6q24 TNDM are sporadic (UPD(6q24)pat and the majority of PLAGL1 hypomethylation cases).1 In these cases, family members are at only population risk. However, for chromosomal aberrations leading to duplication of 6q24 and ZFP57 mutation, there is a risk to family members. Homozygous mutations of ZFP57 and paternal inheritance of 6q24 duplication both carry in principle 100% risk of 6q24 TNDM (though non-penetrance is observed, see earlier). Also balanced chromosome 6 aberrations in one of the parents lead to an increased risk for 6q24 TNDM as part of gain affecting 6q24 or UPD derived from malsegregation and rescue, respectively. In patients with MLMD, maternal effect mutations might lead to an up to 100% recurrence risk in offspring.
3.3.1 Does the result of a genetic test resolve the genetic situation in that family?
3.3.2 Can a genetic test in the index patient save genetic or other tests in family members?
3.3.3 Does a positive genetic test result in the index patient enable a predictive test in a family member?
3.4 Prenatal diagnosis
(To be answered if in 1.9 ‘D’ was marked)
3.4.1 Does a positive genetic test result in the index patient enable a prenatal diagnosis?
Yes, although see caveat regarding methylation testing. However, due to the rarity of the disorder information is very scarce at present.
4. If applicable, further consequences of testing
Please assume that the result of a genetic test has no immediate medical consequences. Is there any evidence that a genetic test is nevertheless useful for the patient or his/her relatives? (Please describe)
The identification of a mutation or epimutation allows delineation of recurrence risk for the patient and his or her family as well as indicating risk of diabetes recurrence in later life.
Temple IK, Mackay DJG, Docherty LE : Diabetes mellitus, 6q24-related transient neonatal.; In: Pagon RA, Adam MP, Bird TD et al. (eds.): GeneReviews™, (initial posting: 10 Oct 2005; updated 27 Sep 2012) University of Washington: Seattle, WA, USA, 1993–2013.
Docherty LE, Kabwama S, Lehmann A et al: 6q24 Transient Neonatal Diabetes Mellitus (6q24 TNDM)–clinical presentation and genotype phenotype correlation in an international cohort of cases. Diabetologia 2013; 56: 758–762.
Mackay DJ, Callaway JL, Marks SM et al: Hypomethylation of multiple imprinted loci in individuals with transient neonatal diabetes is associated with mutations in ZFP57. Nat Genet 2008; 40: 949–951.
Maupetit-Mehouas S, Azzi S, Steunou V et al: Simultaneous hyper- and hypomethylation at imprinted loci in a subset of patients with GNAS Epimutations underlies a complex and different mechanism of multilocus methylation defect in pseudohypoparathyroidism type 1b. Hum Mutat 2013; 34: 1172–1180.
Metz C, Cavé H, Bertrand AM et al: Neonatal diabetes mellitus: chromosomal analysis in transient and permanent cases. J Pediatr 2002; 141: 483–489.
Begemann M, Leisten I, Soellner L et al: Use of multilocus methylation-specific single nucleotide primer extension (MS-SNuPE) technology in diagnostic testing for human imprinted loci. Epigenetics 2012; 7: 473–481.
Martin-Subero JI, Bibikova M, Mackay D et al: Microarray-based DNA methylation analysis of imprinted loci in a patient with transient neonatal diabetes mellitus. Am J Med Genet A 2008; 146A: 3227–3229.
Wiedemann B, Schober E, Waldhoer T et al: Incidence of neonatal diabetes in Austria-calculation based on the Austrian Diabetes Register. Pediatr Diabetes 2010; 11: 18–23.
Hattersley A, Bruining J, Shield J et al: The diagnosis and management of monogenic diabetes in children and adolescents. Pediatr Diabetes 2009; 10: S33–S42.
Polak M, Cavé H : Neonatal diabetes mellitus: a disease linked to multiple mechanisms. Orphanet J Rare Dis 2007; 2: 12.
Flanagan SE, Patch A, Mackay DJG et al: Mutations in KATP channel genes cause transient neonatal diabetes and permanent diabetes in childhood or adulthood. Diabetes 2007; 56: 1930–1937.
Valerio G, Franzese A, Salerno M et al: Beta-cell dysfunction in classic transient neonatal diabetes is characterized by impaired insulin response to glucose but normal response to glucagon. Diabetes Care 2004; 27: 2405–2408.
Boonen SE, Mackay DJ, Hahnemann JM et al: Transient neonatal diabetes, ZFP57 and hypomethylation of multiple imprinted loci: a detailed follow-up. Diabetes Care 2013; 36: 505–512.
Temple IK, Gardner RJ, Mackay DJ et al: Transient neonatal diabetes: widening the understanding of the etiopathogenesis of diabetes. Diabetes 2000; 49: 1359–1366.
Støy J, Greeley SA, Paz VP et alUnited States Neonatal Diabetes Working Group: Diagnosis and treatment of neonatal diabetes: a United States experience. Pediatr Diabetes 2008; 9: 450–459.
Shield JP, Temple IK, Sabin M et al: An assessment of pancreatic endocrine function and insulin sensitivity in patients with transient neonatal diabetes in remission. Arch Dis Child Fetal Neonatal Ed 2004; 89: F341–F343.
Flanagan SE, Mackay DJ, Greeley SA et al: Hypoglycaemia following diabetes remission in patients with 6q24 methylation defects: expanding the clinical phenotype. Diabetologia 2013; 56: 218–221.
This work was supported by EuroGentest2 (Unit 2: ‘Genetic testing as part of health care’), a Coordination Action under FP7 (Grant Agreement Number 261469) and the European Society of Human Genetics. The authors are members of the COST Action BM1208. DJGM and IKT are supported by Diabetes UK, MRC and NIHR; SB and RS are supported by BMBF (Ministry of Education and Science) in the framework of the consortium ‘Diseases caused by imprinting defects: clinical spectrum and pathogenetic mechanisms’ (FKZ: 01GM0886 and 01GM1114); GPN is partially funded by the I3SNS Program of the Spanish Ministry of Health (CP03/0064; SIVI 1395/09).
The authors declare no conflict of interest.
About this article
Cite this article
Mackay, D., Bens, S., Perez de Nanclares, G. et al. Clinical utility gene card for: Transient Neonatal Diabetes Mellitus, 6q24-related. Eur J Hum Genet 22, 1153 (2014). https://doi.org/10.1038/ejhg.2014.27
Endocrine, Metabolic & Immune Disorders - Drug Targets (2019)
Clinical Pediatric Endocrinology (2018)
ISPAD Clinical Practice Consensus Guidelines 2018: The diagnosis and management of monogenic diabetes in children and adolescents
Pediatric Diabetes (2018)
Clinical Genetics (2017)
Mosaic genome-wide maternal isodiploidy: an extreme form of imprinting disorder presenting as prenatal diagnostic challenge
Clinical Epigenetics (2017)