In the index patient (IV-8) of this MCKD family, the MUC1 -VNTR single cytosine insertion was detected in 7/96 clones in the first screening [Figure 2]c.
Several MCKD families with autosomal-dominant transmission have been reported; however, the specific clinical presentation has not yet reached recognition. It was reported that MUC1 mutation led to ESRD with a higher incidence and at younger age;,, moreover, families with a clearly autosomal-dominant transmission of kidney disease and ESRD by the age of 60 had a higher chance of carrying a MUC1 mutation. Consistent with this, we observed an autosomal-dominant inheritance with incomplete penetrance in a large family of five generations, and three patients in this family had been referred to the nephrologists around their third decades; the patient (III5) whose onset age is the youngest among these three patients who had already developed ESRD.
According to the UCy, although MCKD
is a rare disease, it has been traced in villages of the Paphos district at a "considerably higher incidence" than normal.
The case for the CDKs is particularly complex, with 9 genes mutated in nephronophthisis, 12 in Bardet-Biedl syndrome, at least 3 in MCKD, and at least 4 in autosomal dominant and recessive polycystic kidney disease (PKD), while the list is destined to expand unpredictably.
Two clinically indistinguishable types of MCKD, sharing a similar histologic picture with nephronophthisis, have been characterized to this point.
Bilaterality does not exclude MCDK; however, MCKD is usually unilateral and compatible with life unless the contralateral kidney is impaired or absent.
(271) In the absence of other common links between familial juvenile nephronophthisis, MCKD, and GCK, the main cell-biologic target--ciliary function--forms the most appealing link.