De Vries et al developed a simple checklist to determine if a patient with mental retardation should undergo specialized testing for subtelomeric defects.
Indications to screen a patient with mental retardation:
(1) family history of mental retardation
(2) intrauterine growth retardation
(3) poor growth (failure to thrive) or overgrowth in the postnatal period
(4) >= 2 facial dysmorphic features
(5) >= 1 nonfacial dysmorphic features and/or congenital anomalies
The presence of one or more of these factors may justify the expense of the specialized testing for a subtelomeric defect. Genomic microarray analysis may simplify testing and make it more cost-effective.
The above list is based on a more complete checklist (Table 2, page 148, De Vries et al):
Parameters for the checklist:
(1) family history
(2) prenatal onset of growth retardation
(3) postnatal growth abnormalities
(4) facial dysmorphic features (hypertelorism, nasal anomalies, ear anomalies, other)
(5) nonfacial dysmorphisms and congenital abnormalities
|
Parameter
|
Finding
|
Points
|
|
family history
|
none
|
0
|
|
|
compatible with Mendelian inheritance
|
1
|
|
|
not compatible with Mendelian inheritance
|
2
|
|
prenatal onset of growth retardation
|
none
|
0
|
|
|
present
|
2
|
|
postnatal growth abnormalities
|
none
|
0
|
|
|
1 point each for microcephaly, short stature, macrocephaly, tall stature
|
MIN(2, number present)
|
|
facial dysmorphic features
|
none
|
0
|
|
|
1
|
0
|
|
|
2 or more
|
2
|
|
nonfacial dysmorphic features and/or congenital abnormalities
|
1 point each for: hand anomaly, heart anomaly, hypospadias, other
|
MIN(2, number present)
|
total checklist score =
= SUM(points for all 5 parameters(
Interpretation:
• minimum score: 0
• maximum score: 10
• A score >= 3 was 100% sensitive and 27% specific for a subtelomeric defect.
