This is an extremely rare syndrome, so far having been described in only a single family having four affected patients. The condition is characterized by, small echogenic, nephrocalcinic kidneys, leading to distal renal tubular acidosis, hypercalcemia, hypercalciuria, normal anion gap metabolic acidosis, and proteinuria, and characteristic facial features including large bulbous nose, thick ala nasi, well defined philtrum, full lower lips, ear lobule pits, chubby cheeks, protruded tongues, and open mouths. Patients also show mental retardation and a short stature.
Faqeih et al. (2007) described a consanguineous Saudi family, in which four children were affected with what they considered a novel genetic condition. The eldest patient in the family was a 19-year old girl, who had earlier shown neonatal jaundice and developmental delay. Mental development was retarded, and neuropsychological function was significantly delayed at the age of 14-years, with no motor, social, communication, or behavioral progress seen by the age of 16-years. Neurological evaluation demonstrated increased tone, brisk deep tendon reflexes, and wide-based gait. She also showed dilated ventricular system and bilateral periventricular white matter hypodensity on head CT and brain MRI. Small sized kidneys with poor cortico-medullary differentiation, indicating nephrocalcinosis were also visible on renal US. The patient had a short stature, below the 3rd centile for her age, and had mild, microcytic hypochromic anemia. She had peculiar facial features, including a round face with short forehead, deep-set eyes, chubby cheeks, a large bulbous nose with thickened ala nasi and anteverted nares, a short well-defined philtrum, open mouth with a protruded tongue, a full lower lip, crowded and malpositioned teeth, and broad central incisors. Eythematous papular lesions were seen all over the trunk and extremities. Three other siblings, all boys, presented with similar features. At the time of presentation, they were aged 17-years, 13-years and 18-months. Six siblings were unaffected, although one other sibling had died in neonatal period of severe hydrops and renal impairment. There was no earlier family history of a similar condition. Faqeih et al. (2007) differentiated this condition from other classical disorders, such as hyperparathyroidism, hypophosphatemic rickets, Williams syndrome, multiple endocrine neoplasia, and Dent disease, and suggested that these patients may represent a new syndrome, following an autosomal recessive mode of inheritance.