Correspondence

Correction

Neonatal Diabetes Mellitus

N Engl J Med 1996; 334:58-59January 4, 1996

Article

To the Editor:

The data on neonatal diabetes mellitus reported by von Mühlendahl and Herkenhoff (Sept. 14 issue)1 indicate that the causes of this rare condition are heterogeneous. Among the 57 infants, only 7 were known to have HLA haplotypes associated with autoimmune diabetes. In most of the cases, the cause was unknown, and several infants also had very rare genetic disorders. The authors, however, failed to mention some published reports of cases of neonatal diabetes in which a cause could be demonstrated or suggested. The causes included pancreatic aplasia, a congenital absence of the islets, and selective agenesis of β cells.2

In one of the cases involving selective agenesis of β cells, we demonstrated paternal isodisomy of chromosome 6 (i.e., the chromosome pair consisted of two copies of the same paternal chromosome instead of following the normal pattern of biparental inheritance),3 and Temple and colleagues found paternal isodisomy 6 in two neonates with transient diabetes.4 These findings suggest that a subgroup of cases of neonatal diabetes may result from anomalies of chromosome 6, with a mutation or imprinting (i.e., differential expression of a gene depending on the parent of origin) of a putative gene involved in β-cell development located on that chromosome. Parental imprinting may also explain some familial recurrences that do not follow mendelian rules of inheritance.4 From a practical standpoint, the detection of uniparental disomy of chromosome 6 in patients with neonatal diabetes may help identify a subgroup of patients in whom the disorder has a different pathogenicity and prognosis.

Marc J. Abramowicz, M.D.
Harry Dorchy, M.D.
Esther Vamos, M.D.
Erasme Hospital, B-1070 Brussels, Belgium

4 References

1. 1

   von Muhlendahl KE, Herkenhoff H. Long-term course of neonatal diabetes. N Engl J Med 1995;333:704-708
   Full Text | Web of Science | Medline

2. 2

   Blum D, Dorchy H, Mouraux T, et al. Congenital absence of insulin cells in a neonate with diabetes mellitus and mutase-deficient methylmalonic acidaemia. Diabetologia 1993;36:352-357
   CrossRef | Web of Science | Medline

3. 3

   Abramowicz MJ, Andrien M, Dupont E, et al. Isodisomy of chromosome 6 in a newborn with methylmalonic acidemia and agenesis of pancreatic beta cells causing diabetes mellitus. J Clin Invest 1994;94:418-421
   CrossRef | Web of Science | Medline

4. 4

   Temple IK, James RS, Crolla JA, et al. An imprinted gene(s) for diabetes? Nat Genet 1995;9:110-112
   CrossRef | Web of Science | Medline

To the Editor:

There are two pieces of misinformation about the patient described in my case report (Patient 32 and reference 25 in the article by von Mühlendahl and Herkenhoff). First, the duration of hyperglycemia was from day 1 to week 14 (day 98) of life, not to day 14 of life, as indicated in the authors' Table 2. This duration of hyperglycemia is similar to that in the other patients in the group. Second, microalbuminuria subsequently developed in this patient, making the authors' statement that no patient in the group with transient neonatal diabetes and later recurrences had microangiopathy incorrect. (I was not contacted for follow-up information.)

Mitchell E. Geffner, M.D.
UCLA Medical Center, Los Angeles, CA 90095

Author/Editor Response

The authors reply:

To the Editor: We thank Abramowicz et al., for calling our attention to the identification of paternal isodisomy of chromosome 6 in some cases of neonatal diabetes mellitus, and Dr. Geffner, for the correction and additional information about his patient. Further follow-up of the patients in our survey is under way and may well reveal that over time, more patients have microangiopathy.

Karl Ernst von Mühlendahl, M.D.
Heiner Herkenhoff, M.D.
Kinderhospital, D-49082 Osnabrück, Germany