**Question:** The following are the features of "dystocia dystrophica syndrome" except:

A. Hypotonia
B. Respiratory distress
C. Hypoglycaemia
D. Hyperkalemia

**Core Concept:** Dystocia dystrophica syndrome is a rare genetic disorder characterized by muscle weakness (hypotonia), respiratory distress, and hypoglycaemia due to deficient creatine kinase (CK) activity. CK is an enzyme involved in the maintenance of cellular energy (ATP) by catalyzing the conversion of creatine phosphate to adenosine triphosphate (ATP) and phosphocreatine (PCr).

**Why the Correct Answer is Right:** Option D (hyperkalemia) is not a feature of dystocia dystrophica syndrome because the syndrome is characterized by muscle weakness, respiratory distress, and hypoglycaemia. Hyperkalemia is a condition characterized by abnormally high potassium levels in the blood, which is unrelated to the pathogenesis of dystocia dystrophica syndrome.

**Why Each Wrong Option is Incorrect:**

**Option A (Hypotonia)**: This is a correct feature of dystocia dystrophica syndrome, as it is a primary manifestation of the syndrome due to muscle weakness caused by deficient CK activity.

**Option B (Respiratory distress)**: Respiratory distress is another correct feature of the syndrome, as the muscle weakness affects respiratory muscles, leading to difficulties in breathing.

**Option C (Hypoglycaemia)**: Hypoglycaemia is a correct feature of dystocia dystrophica syndrome, as the deficiency of CK results in reduced ATP production and increased breakdown of glycogen, leading to low blood glucose levels (hypoglycaemia).

**Clinical Pearl / High-Yield Fact:** Creatine kinase deficiency can also lead to other conditions, such as hyperkalemia, which should be avoided while diagnosing and treating patients with CK deficiency. This highlights the importance of considering the entire spectrum of clinical manifestations when evaluating patients with CK deficiency-related disorders.