Cockayne syndrome in siblings
Cockayne syndrome (CS) is characterized by postnatal growth failure and progressive neurologic dysfunction with cachectic appearance. Other features include retinal dystrophy, photosensitivity, cataract, and microcephaly.

The present case has been published in the journal Neurology India. Two siblings (elder sister and younger brother), born out of nonconsanguineous parentage were brought by their parents for progressive difficulty in walking. The first child was a 22-year old female patient who had normal growth and development till the age of 12 years.

Thereafter, her parents noticed unsteadiness in walking and tightness of her lower limbs. Her facial appearance also started changing with signs of premature aging. She progressively worsened and suffered occasional falls. She had attained her menarche at the age of 12 years and her menstrual cycles were regular.

On examination, she was cachectic and stunted with a height of 136 cm and a weight of 34 kg. Her head circumference was 46 cm, which qualified for microcephaly [Figure 1]. She had malaligned teeth. She had normal secondary sexual characteristics. The cardiac evaluation was normal. She had corneal opacity in her left eye.

Neurological examination revealed appendicular and axial ataxia, spastic paraparesis, bilateral sensory neural hearing loss, and mild cognitive decline. Nerve conduction study revealed sensorimotor axonal polyneuropathy of both upper and lower limb nerves. Her EEG was normal. MRI revealed bilateral basal ganglia calcification, a thin corpus callosum, and cerebral atrophy.

The second sibling, a 20-year old male patient, was brought with similar complaints that had been occurring since 12 years of age. He had a similar facial appearance as his sister. He was cachectic with a height of 140 cm and a weight of 36 kg. He had microcephaly (his head circumference was 48 cm) and mild sensory neural hearing loss.

He had appendicular ataxia and scissoring of gait due to spastic paraplegia. He had left eye optic atrophy, and cardiac evaluation showed premature accelerated aging in the form of aortic valve (AV) sclerosis and dilatation of ascending aorta. He also had mild cognitive decline and normal secondary sexual characters.

The nerve conduction study revealed sensorimotor axonal polyneuropathy of all four limbs. EEG showed a normal awake record. MRI showed bilateral basal ganglia calcification, a thin corpus callosum, and cerebral atrophy, features that were similar to that of his sister.

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