The highest incidence of glycogen storage disease type III is in the Faroe Islands where it occurs in 1 out of every 3,600 births, probably due to a founder effect. There seem to be two mutations in exon 3 (c.17_18delAG) being one of them, which are linked to the subtype IIIb.The amylo-alpha-1, 6-glucosidase, 4-alpha-glucanotransferase gene and mutations to it, are at the root of this condition. The gene is responsible for creating glycogen debranching enzyme, which in turn helps in glycogen decomposition. Diagnosis
In terms of the diagnosis for glycogen storage disease type III, the following tests/exams are carried out to determine if the individual has the condition:
Biopsy (muscle or liver)
CBC
Ultrasound
DNA mutation analysis (helps ascertain GSD III subtype)

Differential diagnosis
The differential diagnosis of glycogen storage disease type III includes GSD I, GSD IX and GSD VI. This however does not mean other glycogen storage diseases should not be distinguished as well. Classification
Clinical manifestations of glycogen storage disease type III are divided into four classes:
GSD IIIa, is the most common, (along with GSD IIIb) and which clinically includes muscle and liver involvement
GSD IIIb, which clinically has liver involvement but no muscle involvement
GSD IIIc  which clinically affects liver and muscle. GSD IV affects liver only (not muscle)

Treatment
Treatment for glycogen storage disease type III may involve a high-protein diet, in order to facilitate gluconeogenesis. Additionally the individual may need:
IV glucose (if oral route is inadvisable)
Nutritional specialist
Vitamin D (for osteoporosis/secondary complication)
Hepatic transplant (if complication occurs)

References
Further reading
Mayorandan, Sebene; Meyer, Uta; Hartmann, Hans; Das, Anibh Martin (1 January 2014).
Acromicric dysplasia is an extremely rare inherited disorder characterized by abnormally short hands and feet, growth retardation and delayed bone maturation leading to short stature. Most cases have occurred randomly for no apparent reason (sporadically). However, autosomal dominant inheritance has not been ruled out. The disorder is different (but similar to) from other syndromic entities such as geleophysic dysplasia, Weill-Marchesani syndrome, and Myhre syndrome. Genetics
This condition has been associated with mutations in the Fibrillin 1 (FBN1) gene.Mutations in this gene have also been associated with stiff skin syndrome, Marfan syndrome and its variant Marfanoid–progeroid–lipodystrophy syndrome, autosomal dominant Weill-Marchesani syndrome, isolated ectopia lentis, MASS phenotype, and Shprintzen-Goldberg syndrome. References
External links
GeneReview/NIH/UW entry on Geleophysic Dysplasia